Skip to main content

Research Repository

Advanced Search

Outputs (183)

Simulating Z 2 lattice gauge theory with the variational quantum thermalizer (2024)
Journal Article
Fromm, M., Philipsen, O., Spannowsky, M., & Winterowd, C. (2024). Simulating Z 2 lattice gauge theory with the variational quantum thermalizer. EPJ Quantum Technology, 11(1), 20. https://doi.org/10.1140/epjqt/s40507-024-00232-2

The properties of strongly-coupled lattice gauge theories at finite density as well as in real time have largely eluded first-principles studies on the lattice. This is due to the failure of importance sampling for systems with a complex action. An a... Read More about Simulating Z 2 lattice gauge theory with the variational quantum thermalizer.

Hypergraphs in LHC phenomenology — the next frontier of IRC-safe feature extraction (2024)
Journal Article
Konar, P., Ngairangbam, V. S., & Spannowsky, M. (2024). Hypergraphs in LHC phenomenology — the next frontier of IRC-safe feature extraction. Journal of High Energy Physics, 2024(1), Article 113. https://doi.org/10.1007/jhep01%282024%29113

In this study, we critically evaluate the approximation capabilities of existing infra-red and collinear (IRC) safe feature extraction algorithms, namely Energy Flow Networks (EFNs) and Energy-weighted Message Passing Networks (EMPNs). Our analysis r... Read More about Hypergraphs in LHC phenomenology — the next frontier of IRC-safe feature extraction.

Quantum-probabilistic Hamiltonian learning for generative modeling and anomaly detection (2023)
Journal Article
Araz, J. Y., & Spannowsky, M. (2023). Quantum-probabilistic Hamiltonian learning for generative modeling and anomaly detection. Physical Review A, 108(6), Article 062422. https://doi.org/10.1103/physreva.108.062422

The Hamiltonian of an isolated quantum-mechanical system determines its dynamics and physical behavior. This study investigates the possibility of learning and utilizing a system's Hamiltonian and its variational thermal state estimation for data ana... Read More about Quantum-probabilistic Hamiltonian learning for generative modeling and anomaly detection.

FeynMG: A FeynRules extension for scalar-tensor theories of gravity (2023)
Journal Article
Sevillano Muñoz, S., Copeland, E. J., Millington, P., & Spannowsky, M. (2024). FeynMG: A FeynRules extension for scalar-tensor theories of gravity. Computer Physics Communications, 296, Article 109035. https://doi.org/10.1016/j.cpc.2023.109035

The ability to represent perturbative expansions of interacting quantum field theories in terms of simple diagrammatic rules has revolutionized calculations in particle physics (and elsewhere). Moreover, these rules are readily automated, a process t... Read More about FeynMG: A FeynRules extension for scalar-tensor theories of gravity.

Probing Poincaré violation (2023)
Journal Article
Gupta, R., Jaeckel, J., & Spannowsky, M. (2023). Probing Poincaré violation. Journal of High Energy Physics, 2023(11), 26. https://doi.org/10.1007/jhep11%282023%29026

Time and space translation invariance, giving rise to energy and momentum conservation, are not only amongst the most fundamental but also the most generally accepted symmetry assumptions in physics. It is nevertheless prudent to put such assumptions... Read More about Probing Poincaré violation.

Toward a quantum simulation of nonlinear sigma models with a topological term (2023)
Journal Article
Araz, J. Y., Schenk, S., & Spannowsky, M. (2023). Toward a quantum simulation of nonlinear sigma models with a topological term. Physical Review A, 107(3), https://doi.org/10.1103/physreva.107.032619

We determine the mass gap of a two-dimensional O(3) nonlinear sigma model augmented with a topological θ-term using tensor network and digital quantum algorithms. As proof of principle, we consider the example θ=π and study its critical behavior on a... Read More about Toward a quantum simulation of nonlinear sigma models with a topological term.

Effective limits on single scalar extensions in the light of recent LHC data (2023)
Journal Article
Anisha, Das Bakshi, S., Banerjee, S., Biekötter, A., Chakrabortty, J., Patra, S. K., & Spannowsky, M. (2023). Effective limits on single scalar extensions in the light of recent LHC data. Physical Review D, 107(5), Article 055028. https://doi.org/10.1103/physrevd.107.055028

In this paper, we work with 16 different single scalar particle extensions of the Standard Model. We present the sets of dimension-six effective operators and the associated Wilson coefficients as functions of model parameters after integrating out t... Read More about Effective limits on single scalar extensions in the light of recent LHC data.

Integrating out heavy scalars with modified equations of motion: Matching computation of dimension-eight SMEFT coefficients (2023)
Journal Article
Banerjee, U., Chakrabortty, J., Englert, C., Rahaman, S. U., & Spannowsky, M. (2023). Integrating out heavy scalars with modified equations of motion: Matching computation of dimension-eight SMEFT coefficients. Physical Review D, 107(5), Article 055007. https://doi.org/10.1103/physrevd.107.055007

The shift in focus towards searches for physics beyond the Standard Model employing model-independent effective field theory methods necessitates a rigorous approach to matching to guarantee the validity of the obtained results and constraints. The l... Read More about Integrating out heavy scalars with modified equations of motion: Matching computation of dimension-eight SMEFT coefficients.

Quantum fitting framework applied to effective field theories (2023)
Journal Article
Criado, J. C., Spannowsky, M., & Kogler, R. (2023). Quantum fitting framework applied to effective field theories. Physical Review D, 107(1), Article 015023. https://doi.org/10.1103/physrevd.107.015023

The use of experimental data to constrain the values of the Wilson coefficients of an effective field theory involves minimizing a χ2 function that may contain local minima. Classical optimization algorithms can become trapped in these minima, preven... Read More about Quantum fitting framework applied to effective field theories.

Qade: solving differential equations on quantum annealers (2022)
Journal Article
Criado, J. C., & Spannowsky, M. (2023). Qade: solving differential equations on quantum annealers. Quantum Science and Technology, 8(1), Article 015021. https://doi.org/10.1088/2058-9565/acaa51

We present a general method, called Qade, for solving differential equations using a quantum annealer. One of the main advantages of this method is its flexibility and reliability. On current devices, Qade can solve systems of coupled partial differe... Read More about Qade: solving differential equations on quantum annealers.

Simulating anti-skyrmions on a lattice (2022)
Journal Article
Criado, J. C., Schenk, S., Spannowsky, M., Hatton, P. D., & Turnbull, L. (2022). Simulating anti-skyrmions on a lattice. Scientific Reports, 12, Article 19179. https://doi.org/10.1038/s41598-022-22043-0

Magnetic skyrmions are topological spin structures that naturally emerge in magnetic materials. While a vast amount of effort has gone into the study of their properties, their counterpart of opposite topological charge, the anti-skyrmion, has not re... Read More about Simulating anti-skyrmions on a lattice.

Collider events on a quantum computer (2022)
Journal Article
Gustafson, G., Prestel, S., Spannowsky, M., & Williams, S. (2022). Collider events on a quantum computer. Journal of High Energy Physics, 2022(11), Article 35. https://doi.org/10.1007/jhep11%282022%29035

An intuitive definition of the partonic flavor of a jet in quantum chromodynamics is often only well-defined in the deep ultraviolet, where the strong force becomes a free theory and a jet consists of a single parton. However, measurements are perfor... Read More about Collider events on a quantum computer.

Quantum optimization of complex systems with a quantum annealer (2022)
Journal Article
Abel, S., Blance, A., & Spannowsky, M. (2022). Quantum optimization of complex systems with a quantum annealer. Physical Review A, 106(4), https://doi.org/10.1103/physreva.106.042607

We perform an in-depth comparison of quantum annealing with several classical optimization techniques, namely, thermal annealing, Nelder-Mead, and gradient descent. The focus of our study is large quasicontinuous potentials that must be encoded using... Read More about Quantum optimization of complex systems with a quantum annealer.

New Higgs decays to axion-like particles (2022)
Journal Article
Biekötter, A., Chala, M., & Spannowsky, M. (2022). New Higgs decays to axion-like particles. Physics Letters B, 834, Article 137465. https://doi.org/10.1016/j.physletb.2022.137465

We investigate the interactions of a light scalar with the Higgs boson and second-generation fermions, which trigger new rare decays of the Higgs boson into 4μ, 2μ2γ , 6μ and 4μ2 j. We recast current LHC searches to constrain these decays and develop... Read More about New Higgs decays to axion-like particles.

Quantum walk approach to simulating parton showers (2022)
Journal Article
Bepari, K., Malik, S., Spannowsky, M., & Williams, S. (2022). Quantum walk approach to simulating parton showers. Physical Review D, 106(5), https://doi.org/10.1103/physrevd.106.056002

This paper presents a novel quantum walk approach to simulating parton showers on a quantum computer. We demonstrate that the quantum walk paradigm offers a natural and more efficient approach to simulating parton showers on quantum devices, with the... Read More about Quantum walk approach to simulating parton showers.

A duality connecting neural network and cosmological dynamics (2022)
Journal Article
Krippendorf, S., & Spannowsky, M. (2022). A duality connecting neural network and cosmological dynamics. Machine Learning: Science and Technology, 3(3), https://doi.org/10.1088/2632-2153/ac87e9

We demonstrate that the dynamics of neural networks (NNs) trained with gradient descent and the dynamics of scalar fields in a flat, vacuum energy dominated Universe are structurally profoundly related. This duality provides the framework for synergi... Read More about A duality connecting neural network and cosmological dynamics.

Coloring mixed QCD/QED evolution (2022)
Journal Article
Gellersen, L., Prestel, S., & Spannowsky, M. (2022). Coloring mixed QCD/QED evolution. SciPost Physics, 13(2), https://doi.org/10.21468/scipostphys.13.2.034

Parton showers are crucial components of high-energy physics calculations. Improving their modelling of QCD is an active research area since shower approximations are stumbling blocks for precision event generators. Naively, the interference between... Read More about Coloring mixed QCD/QED evolution.

Completely quantum neural networks (2022)
Journal Article
Abel, S., Criado, J. C., & Spannowsky, M. (2022). Completely quantum neural networks. Physical Review A, 106(2), Article 022601. https://doi.org/10.1103/physreva.106.022601

Artificial neural networks are at the heart of modern deep learning algorithms. We describe how to embed and train a general neural network in a quantum annealer without introducing any classical element in training. To implement the network on a sta... Read More about Completely quantum neural networks.

IRC-Safe Graph Autoencoder for Unsupervised Anomaly Detection (2022)
Journal Article
Atkinson, O., Bhardwaj, A., Englert, C., Konar, P., Ngairangbam, V. S., & Spannowsky, M. (2022). IRC-Safe Graph Autoencoder for Unsupervised Anomaly Detection. Frontiers in Artificial Intelligence, 5, Article 943135. https://doi.org/10.3389/frai.2022.943135

Anomaly detection through employing machine learning techniques has emerged as a novel powerful tool in the search for new physics beyond the Standard Model. Historically similar to the development of jet observables, theoretical consistency has not... Read More about IRC-Safe Graph Autoencoder for Unsupervised Anomaly Detection.

Secluded dark matter in gauged B − L model (2022)
Journal Article
Bandyopadhyay, P., Mitra, M., Padhan, R., Roy, A., & Spannowsky, M. (2022). Secluded dark matter in gauged B − L model. Journal of High Energy Physics, 2022(5), Article 182. https://doi.org/10.1007/jhep05%282022%29182

We consider the gauged B − L model which is extended with a secluded dark sector, comprising of two dark sector particles. In this framework the lightest Z2-odd particle is the dark matter candidate, having a feeble interaction with all other SM and... Read More about Secluded dark matter in gauged B − L model.

Anomaly detection in high-energy physics using a quantum autoencoder (2022)
Journal Article
Ngairangbam, V. S., Spannowsky, M., & Takeuchi, M. (2022). Anomaly detection in high-energy physics using a quantum autoencoder. Physical Review D, 105(9), Article 095004. https://doi.org/10.1103/physrevd.105.095004

The lack of evidence for new interactions and particles at the Large Hadron Collider (LHC) has motivated the high-energy physics community to explore model-agnostic data-analysis approaches to search for new physics. Autoencoders are unsupervised mac... Read More about Anomaly detection in high-energy physics using a quantum autoencoder.

Unsupervised Quark/Gluon Jet Tagging With Poissonian Mixture Models (2022)
Journal Article
Alvarez, E., Spannowsky, M., & Szewc, M. (2022). Unsupervised Quark/Gluon Jet Tagging With Poissonian Mixture Models. Frontiers in Artificial Intelligence, 5, Article 852970. https://doi.org/10.3389/frai.2022.852970

The classification of jets induced by quarks or gluons is important for New Physics searches at high-energy colliders. However, available taggers usually rely on modeling the data through Monte Carlo simulations, which could veil intractable theoreti... Read More about Unsupervised Quark/Gluon Jet Tagging With Poissonian Mixture Models.

High energy lepton colliders as the ultimate Higgs microscopes (2022)
Journal Article
Banerjee, S., Gupta, R. S., Ochoa-Valeriano, O., & Spannowsky, M. (2022). High energy lepton colliders as the ultimate Higgs microscopes. Journal of High Energy Physics, 2022(2), Article 176. https://doi.org/10.1007/jhep02%282022%29176

We study standard electroweak/Higgs processes at the high-energy lepton colliders ILC and CLIC. We identify a subset of three operators in the SMEFT that give leading contributions to these processes at high energies. We then perform a ‘high-energy f... Read More about High energy lepton colliders as the ultimate Higgs microscopes.

Energy-weighted message passing: an infra-red and collinear safe graph neural network algorithm (2022)
Journal Article
Konar, P., Ngairangbam, V. S., & Spannowsky, M. (2022). Energy-weighted message passing: an infra-red and collinear safe graph neural network algorithm. Journal of High Energy Physics, 2022(2), Article 60. https://doi.org/10.1007/jhep02%282022%29060

Hadronic signals of new-physics origin at the Large Hadron Collider can remain hidden within the copiously produced hadronic jets. Unveiling such signatures require highly performant deep-learning algorithms. We construct a class of Graph Neural Netw... Read More about Energy-weighted message passing: an infra-red and collinear safe graph neural network algorithm.

Landscaping CP-violating BSM scenarios (2022)
Journal Article
Das Bakshi, S., Chakrabortty, J., Englert, C., Spannowsky, M., & Stylianou, P. (2022). Landscaping CP-violating BSM scenarios. Nuclear Physics B, 975, https://doi.org/10.1016/j.nuclphysb.2022.115676

We consider a wide range of UV scenarios with the aim of informing searches for CP violation at the TeV scale using effective field theory techniques. We demonstrate that broad theoretical assumptions about the nature of UV dynamics responsible for C... Read More about Landscaping CP-violating BSM scenarios.

Electroweak skyrmions in the HEFT (2021)
Journal Article
Criado, J. C., Khoze, V. V., & Spannowsky, M. (2021). Electroweak skyrmions in the HEFT. Journal of High Energy Physics, 2021(12), Article 26. https://doi.org/10.1007/jhep12%282021%29026

We study the existence of skyrmions in the presence of all the electroweak degrees of freedom, including a dynamical Higgs boson, with the electroweak symmetry being non-linearly realized in the scalar sector. For this, we use the formulation of the... Read More about Electroweak skyrmions in the HEFT.

Small instantons and the strong CP problem in composite Higgs models (2021)
Journal Article
Gupta, R., Khoze, V., & Spannowsky, M. (2021). Small instantons and the strong CP problem in composite Higgs models. Physical Review D, 104(7), Article 075011. https://doi.org/10.1103/physrevd.104.075011

We show that QCD instantons can generate large effects at small length scales in the ultraviolet in standard composite Higgs models that utilize partial compositeness. This has important implications for possible solutions of the strong CP problem in... Read More about Small instantons and the strong CP problem in composite Higgs models.

Probing dark matter clumps, strings and domain walls with gravitational wave detectors (2021)
Journal Article
Jaeckel, J., Schenk, S., & Spannowsky, M. (2021). Probing dark matter clumps, strings and domain walls with gravitational wave detectors. The European Physical Journal C, 81(9), Article 828. https://doi.org/10.1140/epjc/s10052-021-09604-9

Gravitational wave astronomy has recently emerged as a new way to study our Universe. In this work, we survey the potential of gravitational wave interferometers to detect macroscopic astrophysical objects comprising the dark matter. Starting from th... Read More about Probing dark matter clumps, strings and domain walls with gravitational wave detectors.

Unsupervised event classification with graphs on classical and photonic quantum computers (2021)
Journal Article
Blance, A., & Spannowsky, M. (2021). Unsupervised event classification with graphs on classical and photonic quantum computers. Journal of High Energy Physics, 2021(8), https://doi.org/10.1007/jhep08%282021%29170

Photonic Quantum Computers provide several benefits over the discrete qubit-based paradigm of quantum computing. By using the power of continuous-variable computing we build an anomaly detection model to use on searches for New Physics. Our model use... Read More about Unsupervised event classification with graphs on classical and photonic quantum computers.

Spectral walls in multifield kink dynamics (2021)
Journal Article
Adam, C., Oles, K., Romanczukiewicz, T., Wereszczynski, A., & Zakrzewski, W. (2021). Spectral walls in multifield kink dynamics. Journal of High Energy Physics, 2021(8), https://doi.org/10.1007/jhep08%282021%29147

We show that spectral walls are common phenomena in the dynamics of kinks in (1+1) dimensions. They occur in models based on two or more scalar fields with a nonempty Bogomol’nyi-Prasad-Sommerfield (BPS) sector, hosting two zero modes, where they are... Read More about Spectral walls in multifield kink dynamics.

Anomaly detection with convolutional Graph Neural Networks (2021)
Journal Article
Atkinson, O., Bhardwaj, A., Englert, C., Ngairangbam, V. S., & Spannowsky, M. (2021). Anomaly detection with convolutional Graph Neural Networks. Journal of High Energy Physics, 2021(8), https://doi.org/10.1007/jhep08%282021%29080

We devise an autoencoder based strategy to facilitate anomaly detection for boosted jets, employing Graph Neural Networks (GNNs) to do so. To overcome known limitations of GNN autoencoders, we design a symmetric decoder capable of simultaneously reco... Read More about Anomaly detection with convolutional Graph Neural Networks.

A fully differential SMEFT analysis of the golden channel using the method of moments (2021)
Journal Article
Banerjee, S., Gupta, R. S., Ochoa-Valeriano, O., Spannowsky, M., & Venturini, E. (2021). A fully differential SMEFT analysis of the golden channel using the method of moments. Journal of High Energy Physics, 2021(6), Article 31. https://doi.org/10.1007/jhep06%282021%29031

The Method of Moments is a powerful framework to disentangle the relative contributions of amplitudes of a specific process to its various phase space regions. We apply this method to carry out a fully differential analysis of the Higgs decay channel... Read More about A fully differential SMEFT analysis of the golden channel using the method of moments.

EFT diagrammatica: UV roots of the CP-conserving SMEFT (2021)
Journal Article
Bakshi, S. D., Chakrabortty, J., Prakash, S., Rahaman, S. U., & Spannowsky, M. (2021). EFT diagrammatica: UV roots of the CP-conserving SMEFT. Journal of High Energy Physics, 2021(6), Article 33. https://doi.org/10.1007/jhep06%282021%29033

The Standard Model Effective Field Theory (SMEFT) is an established theoretical framework that parametrises the impact a UV theory has on low-energy observables. Such parametrization is achieved by studying the interactions of SM fields encapsulated... Read More about EFT diagrammatica: UV roots of the CP-conserving SMEFT.

Extended Higgs boson sectors, effective field theory, and Higgs boson phenomenology (2021)
Journal Article
Anisha, Banerjee, U., Chakrabortty, J., Englert, C., & Spannowsky, M. (2021). Extended Higgs boson sectors, effective field theory, and Higgs boson phenomenology. Physical Review D, 103(9), https://doi.org/10.1103/physrevd.103.096009

We consider the phenomenological implications of charged scalar extensions of the Standard Model (SM) Higgs sector in addition to effective field theory (EFT) couplings of this new state to SM matter. We perform a detailed investigation of modificati... Read More about Extended Higgs boson sectors, effective field theory, and Higgs boson phenomenology.

Combine and conquer: event reconstruction with Bayesian Ensemble Neural Networks (2021)
Journal Article
Araz, J. Y., & Spannowsky, M. (2021). Combine and conquer: event reconstruction with Bayesian Ensemble Neural Networks. Journal of High Energy Physics, 2021(4), Article 296. https://doi.org/10.1007/jhep04%282021%29296

Ensemble learning is a technique where multiple component learners are combined through a protocol. We propose an Ensemble Neural Network (ENN) that uses the combined latent-feature space of multiple neural network classifiers to improve the represen... Read More about Combine and conquer: event reconstruction with Bayesian Ensemble Neural Networks.

Towards a quantum computing algorithm for helicity amplitudes and parton showers (2021)
Journal Article
Bepari, K., Malik, S., Spannowsky, M., & Williams, S. (2021). Towards a quantum computing algorithm for helicity amplitudes and parton showers. Physical Review D, 103(7), Article 076020. https://doi.org/10.1103/physrevd.103.076020

The interpretation of measurements of high-energy particle collisions relies heavily on the performance of full event generators, which include the calculation of the hard process and the subsequent parton shower step. With the continuous improvement... Read More about Towards a quantum computing algorithm for helicity amplitudes and parton showers.

Precision SMEFT bounds from the VBF Higgs at high transverse momentum (2021)
Journal Article
Araz, J. Y., Banerjee, S., Gupta, R. S., & Spannowsky, M. (2021). Precision SMEFT bounds from the VBF Higgs at high transverse momentum. Journal of High Energy Physics, 2021(4), Article 125. https://doi.org/10.1007/jhep04%282021%29125

We study the production of Higgs bosons at high transverse momenta via vector-boson fusion (VBF) in the Standard Model Effective Field Theory (SMEFT). We find that contributions from four independent operator combinations dominate in this limit. Thes... Read More about Precision SMEFT bounds from the VBF Higgs at high transverse momentum.

Exploring instantons in nonlinear sigma models with spin-lattice systems (2021)
Journal Article
Schenk, S., & Spannowsky, M. (2021). Exploring instantons in nonlinear sigma models with spin-lattice systems. Physical Review B, 103(14), Article 144436. https://doi.org/10.1103/physrevb.103.144436

Instanton processes are present in a variety of quantum field theories relevant to high energy as well as condensed matter physics. While they have led to important theoretical insights and physical applications, their underlying features often remai... Read More about Exploring instantons in nonlinear sigma models with spin-lattice systems.

Quantum-Field-Theoretic Simulation Platform for Observing the Fate of the False Vacuum (2021)
Journal Article
Abel, S., & Spannowsky, M. (2021). Quantum-Field-Theoretic Simulation Platform for Observing the Fate of the False Vacuum. PRX Quantum, 2(1), Article 010349. https://doi.org/10.1103/prxquantum.2.010349

We design and implement a quantum annealing simulation platform to observe and study dynamical processes in quantum field theory (QFT). Our approach encodes the field theory as an Ising model, which is then solved by a quantum annealer. As a proof of... Read More about Quantum-Field-Theoretic Simulation Platform for Observing the Fate of the False Vacuum.

Classifying standard model extensions effectively with precision observables (2021)
Journal Article
Das Bakshi, S., Chakrabortty, J., & Spannowsky, M. (2021). Classifying standard model extensions effectively with precision observables. Physical Review D, 103(5), Article 056019. https://doi.org/10.1103/physrevd.103.056019

Effective theories are well established theoretical frameworks to describe the effect of energetically widely separated UV models on observables at lower energy scales. Due to the complexity of the effective theory when taking all the Standard Model... Read More about Classifying standard model extensions effectively with precision observables.

Cosmological bubble friction in local equilibrium (2021)
Journal Article
Balaji, S., Spannowsky, M., & Tamarit, C. (2021). Cosmological bubble friction in local equilibrium. Journal of Cosmology and Astroparticle Physics, 2021(03), Article 051. https://doi.org/10.1088/1475-7516/2021/03/051

In first-order cosmological phase transitions, the asymptotic velocity of expanding bubbles is of crucial relevance for predicting observables like the spectrum of stochastic gravitational waves, or for establishing the viability of mechanisms explai... Read More about Cosmological bubble friction in local equilibrium.

The emergence of electroweak Skyrmions through Higgs bosons (2021)
Journal Article
Criado, J. C., Khoze, V. V., & Spannowsky, M. (2021). The emergence of electroweak Skyrmions through Higgs bosons. Journal of High Energy Physics, 2021(3), Article 162. https://doi.org/10.1007/jhep03%282021%29162

Skyrmions are extended field configurations, initially proposed to describe baryons as topological solitons in an effective field theory of mesons. We investigate and confirm the existence of skyrmions within the electroweak sector of the Standard Mo... Read More about The emergence of electroweak Skyrmions through Higgs bosons.

CP violation at ATLAS in effective field theory (2021)
Journal Article
Das Bakshi, S., Chakrabortty, J., Englert, C., Spannowsky, M., & Stylianou, P. (2021). CP violation at ATLAS in effective field theory. Physical Review D, 103(5), Article 055008. https://doi.org/10.1103/physrevd.103.055008

CP violation beyond the Standard Model (SM) is a crucial missing piece for explaining the observed matter-antimatter asymmetry in the Universe. Recently, the ATLAS experiment at the Large Hadron Collider performed an analysis of electroweak Zjj produ... Read More about CP violation at ATLAS in effective field theory.

Quantum machine learning for particle physics using a variational quantum classifier (2021)
Journal Article
Blance, A., & Spannowsky, M. (2021). Quantum machine learning for particle physics using a variational quantum classifier. Journal of High Energy Physics, 2021, Article 212. https://doi.org/10.1007/jhep02%282021%29212

Quantum machine learning aims to release the prowess of quantum computing to improve machine learning methods. By combining quantum computing methods with classical neural network techniques we aim to foster an increase of performance in solving clas... Read More about Quantum machine learning for particle physics using a variational quantum classifier.

Effective connections of aμ , Higgs physics, and the collider frontier (2021)
Journal Article
Anisha, Banerjee, U., Chakrabortty, J., Englert, C., Spannowsky, M., & Stylianou, P. (2022). Effective connections of aμ , Higgs physics, and the collider frontier. Physical Review D, 105(1), https://doi.org/10.1103/physrevd.105.016019

We consider scalar extensions of the Standard Model (SM) and their effective field theoretic generalizations to illustrate the phenomenological connection between precision measurements of the anomalous magnetic moment of the muon aμ, precision Higgs... Read More about Effective connections of aμ , Higgs physics, and the collider frontier.

Effective operator bases for beyond Standard Model scenarios: an EFT compendium for discoveries (2021)
Journal Article
Banerjee, U., Chakrabortty, J., Prakash, S., Rahaman, S. U., & Spannowsky, M. (2021). Effective operator bases for beyond Standard Model scenarios: an EFT compendium for discoveries. Journal of High Energy Physics, 2021(1), Article 28. https://doi.org/10.1007/jhep01%282021%29028

It is not only conceivable but likely that the spectrum of physics beyond the Standard Model (SM) is non-degenerate. The lightest non-SM particle may reside close enough to the electroweak scale that it can be kinematically probed at high-energy expe... Read More about Effective operator bases for beyond Standard Model scenarios: an EFT compendium for discoveries.

Searching for QCD instantons at hadron colliders (2021)
Journal Article
Khoze, V. V., Milne, D. L., & Spannowsky, M. (2021). Searching for QCD instantons at hadron colliders. Physical Review D, 103(1), Article 014017. https://doi.org/10.1103/physrevd.103.014017

QCD instantons are arguably the best motivated yet unobserved nonperturbative effects predicted by the Standard Model. A discovery and detailed study of instanton-generated processes at colliders would provide a new window into the phenomenological e... Read More about Searching for QCD instantons at hadron colliders.

Quantum computing for quantum tunneling (2021)
Journal Article
Abel, S., Chancellor, N., & Spannowsky, M. (2021). Quantum computing for quantum tunneling. Physical Review D, 103(1), Article 016008. https://doi.org/10.1103/physrevd.103.016008

We demonstrate how quantum field theory problems can be practically encoded by using a discretization of the field theory problem into a general Ising model, with the continuous field values being encoded into Ising spin chains. To illustrate the met... Read More about Quantum computing for quantum tunneling.

Higgs self-coupling measurements using deep learning in the bb¯¯bb¯¯ final state (2020)
Journal Article
Amacker, J., Balunas, W., Beresford, L., Bortoletto, D., Frost, J., Issever, C., …Stanislaus, B. (2020). Higgs self-coupling measurements using deep learning in the bb¯¯bb¯¯ final state. Journal of High Energy Physics, 2020(12), Article 115. https://doi.org/10.1007/jhep12%282020%29115

Measuring the Higgs trilinear self-coupling λhhh is experimentally demanding but fundamental for understanding the shape of the Higgs potential. We present a comprehensive analysis strategy for the HL-LHC using di-Higgs events in the four b-quark cha... Read More about Higgs self-coupling measurements using deep learning in the bb¯¯bb¯¯ final state.

Towards the ultimate differential SMEFT analysis (2020)
Journal Article
Banerjee, S., Gupta, R. S., Reiness, J. Y., Seth, S., & Spannowsky, M. (2020). Towards the ultimate differential SMEFT analysis. Journal of High Energy Physics, 2020(9), https://doi.org/10.1007/jhep09%282020%29170

We obtain SMEFT bounds using an approach that utilises the complete multi-dimensional differential information of a process. This approach is based on the fact that at a given EFT order, the full angular distribution in the most important electroweak... Read More about Towards the ultimate differential SMEFT analysis.

Di-Higgs resonance searches in weak boson fusion (2020)
Journal Article
Barman, R. K., Englert, C., Gonçalves, D., & Spannowsky, M. (2020). Di-Higgs resonance searches in weak boson fusion. Physical Review D, 102(5), Article 055014. https://doi.org/10.1103/physrevd.102.055014

The search for di-Higgs final states is typically limited at the LHC to the dominant gluon fusion channels, with weak boson fusion only assuming a spectator role. In this work, we demonstrate that when it comes to searches for resonant structures tha... Read More about Di-Higgs resonance searches in weak boson fusion.

The effective field theory of low scale see-saw at colliders (2020)
Journal Article
Biekötter, A., Chala, M., & Spannowsky, M. (2020). The effective field theory of low scale see-saw at colliders. The European Physical Journal C, 80(8), Article 743. https://doi.org/10.1140/epjc/s10052-020-8339-2

We study the Standard Model effective field theory (νSMEFT) extended with operators involving right-handed neutrinos, focussing on the regime where the right-handed neutrinos decay promptly on collider scales to a photon and a Standard Model neutrino... Read More about The effective field theory of low scale see-saw at colliders.

Power meets Precision to explore the Symmetric Higgs Portal (2020)
Journal Article
Englert, C., Jaeckel, J., Spannowsky, M., & Stylianou, P. (2020). Power meets Precision to explore the Symmetric Higgs Portal. Physics Letters B, 806, Article 135526. https://doi.org/10.1016/j.physletb.2020.135526

We perform a comprehensive study of collider aspects of a Higgs portal scenario that is protected by an unbroken symmetry. If the mass of the Higgs portal scalar is larger than half the Higgs mass, this scenario becomes very difficult to detect. We p... Read More about Power meets Precision to explore the Symmetric Higgs Portal.

Novel B-decay signatures of light scalars at high energy facilities (2019)
Journal Article
Blance, A., Chala, M., Ramos, M., & Spannowsky, M. (2019). Novel B-decay signatures of light scalars at high energy facilities. Physical Review D, 100(11), Article 115015. https://doi.org/10.1103/physrevd.100.115015

We study the phenomenology of light scalars of masses m1 and m2 coupling to heavy flavor-violating vector bosons of mass mV. For m1;2 ≲ few GeV, this scenario triggers the rare B meson decays B0s → 3μþ3μ−, B0 → 3μþ3μ−, Bþ → Kþ3μþ3μ−, and B0s → K03μþ3... Read More about Novel B-decay signatures of light scalars at high energy facilities.

Higgs phenomenology as a probe of sterile neutrinos (2019)
Journal Article
Butterworth, J. M., Chala, M., Englert, C., Spannowsky, M., & Titov, A. (2019). Higgs phenomenology as a probe of sterile neutrinos. Physical Review D, 100(11), Article 115019. https://doi.org/10.1103/physrevd.100.115019

Physics beyond the Standard Model can manifest itself as both new light states and heavy degrees of freedom. In this paper, we assume that the former comprise only a sterile neutrino, N. Therefore, the most agnostic description of the new physics is... Read More about Higgs phenomenology as a probe of sterile neutrinos.

Resolving the tensor structure of the Higgs coupling to Z bosons via Higgs-strahlung (2019)
Journal Article
Banerjee, S., Gupta, R. S., Reiness, J. Y., & Spannowsky, M. (2019). Resolving the tensor structure of the Higgs coupling to Z bosons via Higgs-strahlung. Physical Review D, 100(11), Article 115004. https://doi.org/10.1103/physrevd.100.115004

We propose differential observables for pp → Zðlþl−Þhðb¯bÞ that can be used to completely determine the tensor structure of the hZZ=hZ¯ff couplings relevant to this process in the dimension-six Standard Model (SM) effective field theory. In particula... Read More about Resolving the tensor structure of the Higgs coupling to Z bosons via Higgs-strahlung.

Revisiting the tt¯hh channel at the FCC-hh (2019)
Journal Article
Banerjee, S., Krauss, F., & Spannowsky, M. (2019). Revisiting the tt¯hh channel at the FCC-hh. Physical Review D, 100(7), Article 073012. https://doi.org/10.1103/physrevd.100.073012

The exploration of the scalar sector of the Standard Model is at the core of current and future science programs at collider experiments, with increasing focus on the self-interaction of the Higgs boson. This important parameter of the Higgs sector c... Read More about Revisiting the tt¯hh channel at the FCC-hh.

All-in-one relaxion: A unified solution to five particle-physics puzzles (2019)
Journal Article
Gupta, R., Reiness, J., & Spannowsky, M. (2019). All-in-one relaxion: A unified solution to five particle-physics puzzles. Physical Review D, 100(5), Article 055003. https://doi.org/10.1103/physrevd.100.055003

We present a unified relaxion solution to the five major outstanding issues in particle physics: Higgs mass naturalness, dark matter, matter-antimatter asymmetry, neutrino masses and the strong CP problem. The only additional field content in our con... Read More about All-in-one relaxion: A unified solution to five particle-physics puzzles.

Solving differential equations with neural networks: Applications to the calculation of cosmological phase transitions (2019)
Journal Article
Piscopo, M. L., Spannowsky, M., & Waite, P. (2019). Solving differential equations with neural networks: Applications to the calculation of cosmological phase transitions. Physical Review D, 100(1), Article 016002. https://doi.org/10.1103/physrevd.100.016002

Starting from the observation that artificial neural networks are uniquely suited to solving optimization problems, and most physics problems can be cast as an optimization task, we introduce a novel way of finding a numerical solution to wide classe... Read More about Solving differential equations with neural networks: Applications to the calculation of cosmological phase transitions.

HYTREES: combining matrix elements and parton shower for hypothesis testing (2019)
Journal Article
Prestel, S., & Spannowsky, M. (2019). HYTREES: combining matrix elements and parton shower for hypothesis testing. The European Physical Journal C, 79(7), Article 546. https://doi.org/10.1140/epjc/s10052-019-7030-y

We present a new way of performing hypothesis tests on scattering data, by means of a perturbatively calculable classifier. This classifier exploits the “history tree” of how the measured data point might have evolved out of any simpler (reconstructe... Read More about HYTREES: combining matrix elements and parton shower for hypothesis testing.

Approaching robust EFT limits for CP violation in the Higgs sector (2019)
Journal Article
Englert, C., Galler, P., Pilkington, A., & Spannowsky, M. (2019). Approaching robust EFT limits for CP violation in the Higgs sector. Physical Review D, 99(9), Article 095007. https://doi.org/10.1103/physrevd.99.095007

Constraining CP-violating interactions in effective field theory of dimension six faces two challenges. First, degeneracies in the multidimensional space of Wilson coefficients have to be lifted. Second, quadratic contributions of CP-odd dimension-si... Read More about Approaching robust EFT limits for CP violation in the Higgs sector.

Constraining four-fermion operators using rare top decays (2019)
Journal Article
Chala, M., Santiago, J., & Spannowsky, M. (2019). Constraining four-fermion operators using rare top decays. Journal of High Energy Physics, 2019(4), Article 14. https://doi.org/10.1007/jhep04%282019%29014

New physics can manifest itself by an appreciable increase of the decay rate of top quarks in rare flavour-changing final states. Exploiting the large top quark production rate at the LHC, we bound four-fermion operators contributing to non-resonant... Read More about Constraining four-fermion operators using rare top decays.

Gravitational wave and collider probes of a triplet Higgs sector with a low cutoff (2019)
Journal Article
Chala, M., Ramos, M., & Spannowsky, M. (2019). Gravitational wave and collider probes of a triplet Higgs sector with a low cutoff. The European Physical Journal C, 79(2), Article 156. https://doi.org/10.1140/epjc/s10052-019-6655-1

We study the scalar triplet extension of the standard model with a low cutoff, preventing large corrections to the quadratic masses that would otherwise worsen the hierarchy problem. We explore the reach of LISA to test the parameter space region of... Read More about Gravitational wave and collider probes of a triplet Higgs sector with a low cutoff.

Consistency of Higgsplosion in localizable QFT (2019)
Journal Article
Khoze, V. V., & Spannowsky, M. (2019). Consistency of Higgsplosion in localizable QFT. Physics Letters B, 790, 466-474. https://doi.org/10.1016/j.physletb.2019.01.052

We show that large n-particle production rates derived in the semiclassical Higgsplosion limit of scalar field theoretical models with spontaneous symmetry breaking, are consistent with general principles of localizable quantum field theory. The stri... Read More about Consistency of Higgsplosion in localizable QFT.

Angles on CP-violation in Higgs boson interactions (2019)
Journal Article
Bernlochner, F. U., Englert, C., Hays, C., Lohwasser, K., Mildner, H., Pilkington, A., …Spannowsky, M. (2019). Angles on CP-violation in Higgs boson interactions. Physics Letters B, 790, 372-379. https://doi.org/10.1016/j.physletb.2019.01.043

CP-violation in the Higgs sector remains a possible source of the baryon asymmetry of the universe. Recent differential measurements of signed angular distributions in Higgs boson production provide a general experimental probe of the CP structure of... Read More about Angles on CP-violation in Higgs boson interactions.

Machine learning uncertainties with adversarial neural networks (2019)
Journal Article
Englert, C., Galler, P., Harris, P., & Spannowsky, M. (2019). Machine learning uncertainties with adversarial neural networks. The European Physical Journal C, 79(1), Article 4. https://doi.org/10.1140/epjc/s10052-018-6511-8

Machine Learning is a powerful tool to reveal and exploit correlations in a multi-dimensional parameter space. Making predictions from such correlations is a highly non-trivial task, in particular when the details of the underlying dynamics of a theo... Read More about Machine learning uncertainties with adversarial neural networks.

Adversarially-trained autoencoders for robust unsupervised new physics searches (2019)
Journal Article
Blance, A., Spannowsky, M., & Waite, P. (2019). Adversarially-trained autoencoders for robust unsupervised new physics searches. Journal of High Energy Physics, 2019(10), Article 047. https://doi.org/10.1007/jhep10%282019%29047

Machine learning techniques in particle physics are most powerful when they are trained directly on data, to avoid sensitivity to theoretical uncertainties or an underlying bias on the expected signal. To be able to train on data in searches for new... Read More about Adversarially-trained autoencoders for robust unsupervised new physics searches.

Probing electroweak precision physics via boosted Higgs-strahlung at the LHC (2018)
Journal Article
Banerjee, S., Englert, C., Gupta, R. S., & Spannowsky, M. (2018). Probing electroweak precision physics via boosted Higgs-strahlung at the LHC. Physical Review D, 98(9), Article 095012. https://doi.org/10.1103/physrevd.98.095012

We study the process pp → Zðlþl−Þhðbb¯Þ in the standard model effective field theory (SMEFT) at high energies using subjet techniques to reconstruct the Higgs boson. We show that at high energies this process probes four directions in the dimension-6... Read More about Probing electroweak precision physics via boosted Higgs-strahlung at the LHC.

Searching for processes with invisible particles using a matrix element-based method (2018)
Journal Article
Ferreira de Lima, D. E., Mattelaer, O., & Spannowsky, M. (2018). Searching for processes with invisible particles using a matrix element-based method. Physics Letters B, 787, 100-104. https://doi.org/10.1016/j.physletb.2018.10.044

We propose a fully flexible method to discriminate between signal and background using a matrix element-based method in the presence of multiple invisible particles. The proposed method performs a mapping of the measured final state onto an observabl... Read More about Searching for processes with invisible particles using a matrix element-based method.

Particle physics with gravitational wave detector technology (2018)
Journal Article
Englert, C., Hild, S., & Spannowsky, M. (2018). Particle physics with gravitational wave detector technology. European Physical Society Letters, 123(4), Article 41001. https://doi.org/10.1209/0295-5075/123/41001

Gravitational wave detector technology provides high-precision measurement apparatuses that, if combined with a modulated particle source, have the potential to measure and constrain particle interactions in a novel way, by measuring the pressure cau... Read More about Particle physics with gravitational wave detector technology.

Top quark FCNCs in extended Higgs sectors (2018)
Journal Article
Banerjee, S., Chala, M., & Spannowsky, M. (2018). Top quark FCNCs in extended Higgs sectors. The European Physical Journal C, 78(8), Article 683. https://doi.org/10.1140/epjc/s10052-018-6150-0

The large number of top quarks produced at the LHC and possible future hadron colliders allows to study rare decays of this particle. In many well motivated models of new physics, for example in non-minimal compositeHiggs models, the existence of sca... Read More about Top quark FCNCs in extended Higgs sectors.

Searching for Leptoquarks at IceCube and the LHC (2018)
Journal Article
Dey, U. K., Kar, D., Mitra, M., Spannowsky, M., & Vincent, A. C. (2018). Searching for Leptoquarks at IceCube and the LHC. Physical Review D, 98(3), Article 035014. https://doi.org/10.1103/physrevd.98.035014

In the light of recent experimental results from IceCube, LHC searches for scalar leptoquark, and the flavor anomalies RK and RK , we analyze two scalar leptoquark models with hypercharge Y ¼ 1=6 and Y ¼ 7=6. We consider the 53 high-energy starting e... Read More about Searching for Leptoquarks at IceCube and the LHC.

Behavior of composite resonances breaking lepton flavor universality (2018)
Journal Article
Chala, M., & Spannowsky, M. (2018). Behavior of composite resonances breaking lepton flavor universality. Physical Review D, 98(3), Article 035010. https://doi.org/10.1103/physrevd.98.035010

Within the context of composite Higgs models, recent hints on lepton flavor nonuniversality in B decays can be explained by a vector resonance V with sizeable couplings to the Standard Model leptons ( ℓ ). We argue that, in such a case, spin- 1 / 2 l... Read More about Behavior of composite resonances breaking lepton flavor universality.

Probing the type-II seesaw mechanism through the production of Higgs bosons at a lepton collider (2018)
Journal Article
Agrawal, P., Mitra, M., Niyogi, S., Shil, S., & Spannowsky, M. (2018). Probing the type-II seesaw mechanism through the production of Higgs bosons at a lepton collider. Physical Review D, 98(1), Article 015024. https://doi.org/10.1103/physrevd.98.015024

We investigate the production and decays of doubly-charged Higgs bosons for the Type-II seesaw mechanism at an eþe− collider with two center of mass energies, ffiffiffi s p ¼ 380 GeV and 3 TeV, and analyze the fully hadronic final states in detail. L... Read More about Probing the type-II seesaw mechanism through the production of Higgs bosons at a lepton collider.

hh+Jet production at 100 TeV (2018)
Journal Article
Banerjee, S., Englert, C., Mangano, M. L., Selvaggi, M., & Spannowsky, M. (2018). hh+Jet production at 100 TeV. The European Physical Journal C, 78(4), Article 322. https://doi.org/10.1140/epjc/s10052-018-5788-y

Higgs pair production is a crucial phenomenological process in deciphering the nature of the TeV scale and the mechanism underlying electroweak symmetry breaking. At the Large Hadron Collider, this process is statistically limited. Pushing the energy... Read More about hh+Jet production at 100 TeV.

Searches for vector-like quarks at future colliders and implications for composite Higgs models with dark matter (2018)
Journal Article
Chala, M., Gröber, R., & Spannowsky, M. (2018). Searches for vector-like quarks at future colliders and implications for composite Higgs models with dark matter. Journal of High Energy Physics, 2018(3), Article 040. https://doi.org/10.1007/jhep03%282018%29040

Many composite Higgs models predict the existence of vector-like quarks with masses outside the reach of the LHC, e.g. m Q ≳ 2 TeV, in particular if these models contain a dark matter candidate. In such models the mass of the new resonances is bounde... Read More about Searches for vector-like quarks at future colliders and implications for composite Higgs models with dark matter.

Double-charming Higgs boson identification using machine-learning assisted jet shapes (2018)
Journal Article
Lenz, A., Spannowsky, M., & Tetlalmatzi-Xolocotzi, G. (2018). Double-charming Higgs boson identification using machine-learning assisted jet shapes. Physical Review D, 97(1), Article 016001. https://doi.org/10.1103/physrevd.97.016001

We study the possibility of identifying a boosted resonance that decays into a charm pair against different sources of background using QCD event shapes, which are promoted to jet shapes. Using a set of jet shapes as input to a boosted decision tree,... Read More about Double-charming Higgs boson identification using machine-learning assisted jet shapes.

Jet-associated resonance spectroscopy (2017)
Journal Article
Englert, C., Ferretti, G., & Spannowsky, M. (2017). Jet-associated resonance spectroscopy. The European Physical Journal C, 77(12), Article 842. https://doi.org/10.1140/epjc/s10052-017-5416-2

We present a model-independent study aimed at characterising the nature of possible resonances in the jetphoton or jet-Z final state at hadron colliders. Such resonances are expected in many models of compositeness and would be a clear indication of... Read More about Jet-associated resonance spectroscopy.

Higgs characterisation in the presence of theoretical uncertainties and invisible decays (2017)
Journal Article
Englert, C., Kogler, R., Schulz, H., & Spannowsky, M. (2017). Higgs characterisation in the presence of theoretical uncertainties and invisible decays. The European Physical Journal C, 77(11), Article 789. https://doi.org/10.1140/epjc/s10052-017-5366-8

While the Higgs characterisation programme is well under way, direct signs for new physics beyond the Standard Model remain elusive. Performing a fit of fully differential Higgs production cross sections at the LHC to a subset of Higgs-relevant effec... Read More about Higgs characterisation in the presence of theoretical uncertainties and invisible decays.

Maxi-sizing the trilinear Higgs self-coupling: how large could it be? (2017)
Journal Article
Di Luzio, L., Gröber, R., & Spannowsky, M. (2017). Maxi-sizing the trilinear Higgs self-coupling: how large could it be?. The European Physical Journal C, 77, Article 788. https://doi.org/10.1140/epjc/s10052-017-5361-0

In order to answer the question on how much the trilinear Higgs self-coupling could deviate from its Standard Model value in weakly coupled models, we study both theoretical and phenomenological constraints. As a first step, we discuss this question... Read More about Maxi-sizing the trilinear Higgs self-coupling: how large could it be?.

Higgsplosion: Solving the hierarchy problem via rapid decays of heavy states into multiple Higgs bosons (2017)
Journal Article
Khoze, V. V., & Spannowsky, M. (2018). Higgsplosion: Solving the hierarchy problem via rapid decays of heavy states into multiple Higgs bosons. Nuclear Physics B, 926, 95-111. https://doi.org/10.1016/j.nuclphysb.2017.11.002

We introduce and discuss two inter-related mechanisms operative in the electroweak sector of the Standard Model at high energies. Higgsplosion, the first mechanism, occurs at some critical energy in the 25 to 103 TeV range, and leads to an exponentia... Read More about Higgsplosion: Solving the hierarchy problem via rapid decays of heavy states into multiple Higgs bosons.

Resonant di-Higgs boson production in the bb¯WW Channel: Probing the electroweak phase transition at the LHC (2017)
Journal Article
Huang, T., No, J., Pernié, L., Ramsey-Musolf, M., Safonov, A., Spannowsky, M., & Winslow, P. (2017). Resonant di-Higgs boson production in the bb¯WW Channel: Probing the electroweak phase transition at the LHC. Physical Review D, 96(3), Article 035007. https://doi.org/10.1103/physrevd.96.035007

We analyze the prospects for resonant di-Higgs production searches at the LHC in the bb¯W+W− (W+→ℓ+νℓ, W−→ℓ−ν¯ℓ) channel, as a probe of the nature of the electroweak phase transition in Higgs portal extensions of the Standard Model. In order to maxim... Read More about Resonant di-Higgs boson production in the bb¯WW Channel: Probing the electroweak phase transition at the LHC.

VBS W±W±H production at the HL-LHC and a 100 TeV pp-collider (2017)
Journal Article
Englert, C., Li, Q., Spannowsky, M., Wang, M., & Wang, L. (2017). VBS W±W±H production at the HL-LHC and a 100 TeV pp-collider. International Journal of Modern Physics A, 32(18), Article 1750106. https://doi.org/10.1142/s0217751x17501068

W±W±H production at hadron colliders through vector boson scattering is a so far unconsidered process, which leads to a clean signature of two same-sign charged leptons and two widely separated jets. This process is sensitive to the HHH and WWHH coup... Read More about VBS W±W±H production at the HL-LHC and a 100 TeV pp-collider.

Electroweak oblique parameters as a probe of the trilinear Higgs boson self-interaction (2017)
Journal Article
Kribs, G. D., Maier, A., Rzehak, H., Spannowsky, M., & Waite, P. (2017). Electroweak oblique parameters as a probe of the trilinear Higgs boson self-interaction. Physical Review D, 95(9), Article 093004. https://doi.org/10.1103/physrevd.95.093004

We calculate the two-loop contributions from a modified trilinear Higgs self-interaction, κλλSMvh3, to the electroweak oblique parameters S and T. Using the current bounds on S and T from electroweak measurements, we find the 95% C.L. constraint on t... Read More about Electroweak oblique parameters as a probe of the trilinear Higgs boson self-interaction.

Prospects for new physics in τ→lμμ at current and future colliders (2017)
Journal Article
Hays, C., Mitra, M., Spannowsky, M., & Waite, P. (2017). Prospects for new physics in τ→lμμ at current and future colliders. Journal of High Energy Physics, 2017(5), Article 014. https://doi.org/10.1007/jhep05%282017%29014

The discovery of lepton flavour violating interactions will be striking evidence for physics beyond the Standard Model. Focusing on the three decays τ∓→μ±μ∓μ∓, τ∓→e±μ∓μ∓ and τ∓→e∓μ∓μ±, we evaluate the discovery potential of current and future high-en... Read More about Prospects for new physics in τ→lμμ at current and future colliders.

Boost to h→Zγ: from LHC to future e+e− colliders (2017)
Journal Article
No, J. M., & Spannowsky, M. (2017). Boost to h→Zγ: from LHC to future e+e− colliders. Physical Review D, 95(1), Article 075027. https://doi.org/10.1103/physrevd.95.075027

A precise measurement of the Higgs h→Zγ decay is very challenging at the LHC, due to the very low %SM h→Zγ(Z→ℓℓ) branching fraction and the shortage of kinematic handles to suppress the large SM Zγ background. We show how such a measurement would be... Read More about Boost to h→Zγ: from LHC to future e+e− colliders.

Type-II Seesaw Model and Multilepton Signatures at Hadron Colliders (2017)
Journal Article
Mitra, M., Niyogi, S., & Spannowsky, M. (2017). Type-II Seesaw Model and Multilepton Signatures at Hadron Colliders. Physical Review D, 95(3), Article 035042. https://doi.org/10.1103/physrevd.95.035042

We investigate multilepton signatures, arising from the decays of doubly charged and singly charged Higgs bosons in the Type II seesaw model. Depending on the vacuum expectation value of the triplet vΔ, the doubly and singly charged Higgs bosons can... Read More about Type-II Seesaw Model and Multilepton Signatures at Hadron Colliders.

Invisible decays in Higgs boson pair production (2017)
Journal Article
Banerjee, S., Batell, B., & Spannowsky, M. (2017). Invisible decays in Higgs boson pair production. Physical Review D, 95(3), Article 035009. https://doi.org/10.1103/physrevd.95.035009

Observation of Higgs pair production is an important long term objective of the LHC physics program as it will shed light on the scalar potential of the Higgs field and the nature of electroweak symmetry breaking. While numerous studies have examined... Read More about Invisible decays in Higgs boson pair production.

Quark-gluon tagging with shower deconstruction: Unearthing dark matter and Higgs couplings (2017)
Journal Article
Ferreira de Lima, D., Petrov, P., Soper, D., & Spannowsky, M. (2017). Quark-gluon tagging with shower deconstruction: Unearthing dark matter and Higgs couplings. Physical Review D, 95(3), Article 034001. https://doi.org/10.1103/physrevd.95.034001

The separation of quark and gluon initiated jets can be an important way to improve the sensitivity in searches for new physics or in measurements of Higgs boson properties. We present a simplified version of the shower deconstruction approach as a n... Read More about Quark-gluon tagging with shower deconstruction: Unearthing dark matter and Higgs couplings.

Perturbative Higgs coupling CP violation, unitarity, and phenomenology (2017)
Journal Article
Englert, C., Nordström, K., Sakurai, K., & Spannowsky, M. (2017). Perturbative Higgs coupling CP violation, unitarity, and phenomenology. Physical Review D, 95(1), Article 015018. https://doi.org/10.1103/physrevd.95.015018

Perturbative probability conservation provides a strong constraint on the presence of new interactions of the Higgs boson. In this work we consider CP-violating Higgs interactions in conjunction with unitarity constraints in the gauge-Higgs and fermi... Read More about Perturbative Higgs coupling CP violation, unitarity, and phenomenology.

Sphalerons in composite and non-standard Higgs models (2017)
Journal Article
Spannowsky, M., & Tamarit, C. (2017). Sphalerons in composite and non-standard Higgs models. Physical Review D, 95(1), Article 015006. https://doi.org/10.1103/physrevd.95.015006

After the discovery of the Higgs boson and the rather precise measurement of all electroweak boson’s masses the local structure of the electroweak symmetry breaking potential is already quite well established. However, despite being a key ingredient... Read More about Sphalerons in composite and non-standard Higgs models.

The Higgs Portal and Cosmology (2016)
Presentation / Conference
Assamagan, K., Spannowsky, M., & others. (2016, December). The Higgs Portal and Cosmology

Measurement of W boson angular distributions in events with high transverse momentum jets at s√= 8 TeV using the ATLAS detector (2016)
Journal Article
Aaboud, M., Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Abeloos, B., …Zwalinski, L. (2017). Measurement of W boson angular distributions in events with high transverse momentum jets at s√= 8 TeV using the ATLAS detector. Physics Letters B, 765, 132-153. https://doi.org/10.1016/j.physletb.2016.12.005

The W boson angular distribution in events with high transverse momentum jets is measured using data collected by the ATLAS experiment from proton–proton collisions at a centre-of-mass energy s=8TeV at the Large Hadron Collider, corresponding to an i... Read More about Measurement of W boson angular distributions in events with high transverse momentum jets at s√= 8 TeV using the ATLAS detector.

Hearing the signal of dark sectors with gravitational wave detectors (2016)
Journal Article
Jaeckel, J., Khoze, V. V., & Spannowsky, M. (2016). Hearing the signal of dark sectors with gravitational wave detectors. Physical Review D, 94(10), Article 103519. https://doi.org/10.1103/physrevd.94.103519

Motivated by advanced LIGO (aLIGO)’s recent discovery of gravitational waves, we discuss signatures of new physics that could be seen at ground- and space-based interferometers. We show that a first-order phase transition in a dark sector would lead... Read More about Hearing the signal of dark sectors with gravitational wave detectors.

Jet activity as a probe of diphoton resonance production (2016)
Journal Article
Harland-Lang, L., Khoze, V., Ryskin, M., & Spannowsky, M. (2016). Jet activity as a probe of diphoton resonance production. The European Physical Journal C, 76, Article 623. https://doi.org/10.1140/epjc/s10052-016-4471-4

We explore the method of using the measured jet activity associated with a high-mass resonance state to determine the corresponding production modes. To demonstrate the potential of the approach, we consider the case of a resonance of mass MR decayin... Read More about Jet activity as a probe of diphoton resonance production.

Neutrino jets from high-mass WR gauge bosons in TeV-scale left-right symmetric models (2016)
Journal Article
Mitra, M., Ruiz, R., Scott, D. J., & Spannowsky, M. (2016). Neutrino jets from high-mass WR gauge bosons in TeV-scale left-right symmetric models. Physical Review D, 94(9), Article 095016. https://doi.org/10.1103/physrevd.94.095016

We reexamine the discovery potential at hadron colliders of high-mass right-handed (RH) gauge bosons WR—an inherent ingredient of left-right symmetric models (LRSM).We focus on the regime where theWR is very heavy compared to the heavy Majorana neutr... Read More about Neutrino jets from high-mass WR gauge bosons in TeV-scale left-right symmetric models.

LHC Signatures Of Scalar Dark Energy (2016)
Journal Article
Brax, P., Burrage, C., Englert, C., & Spannowsky, M. (2016). LHC Signatures Of Scalar Dark Energy. Physical Review D, 94(8), Article 084054. https://doi.org/10.1103/physrevd.94.084054

Scalar dark energy fields that couple to the standard model can give rise to observable signatures at the LHC. In this work, we show that t¯t þ missing energy and monojet searches are suitable probes in the limit where the dark energy scalar is stabl... Read More about LHC Signatures Of Scalar Dark Energy.

A facility to search for hidden particles at the CERN SPS: the SHiP physics case. (2016)
Journal Article
Altmannshofer, W., Asaka, T., Batell, B., Bezrukov, F., Bondarenko, K., Boyarsky, A., …Zurek, K. M. (2016). A facility to search for hidden particles at the CERN SPS: the SHiP physics case. Reports on Progress in Physics, 79(12), Article 124201. https://doi.org/10.1088/0034-4885/79/12/124201

The standard model of elementary particle physics has provided a consistent description of Nature's fundamental constituents and their interactions. Its predictions have been tested and confirmed by numerous experiments. The Large Hadron Collider's r... Read More about A facility to search for hidden particles at the CERN SPS: the SHiP physics case..

S-Channel Dark Matter Simplified Models and Unitarity (2016)
Journal Article
Englert, C., McCullough, M., & Spannowsky, M. (2016). S-Channel Dark Matter Simplified Models and Unitarity. Physics of the Dark Universe, 14, 48-56. https://doi.org/10.1016/j.dark.2016.09.002

The ultraviolet structure of -channel mediator dark matter simplified models at hadron colliders is considered. In terms of commonly studied -channel mediator simplified models it is argued that at arbitrarily high energies the perturbative descripti... Read More about S-Channel Dark Matter Simplified Models and Unitarity.

Towards resolving strongly-interacting dark sectors at colliders (2016)
Journal Article
Englert, C., Nordström, K., & Spannowsky, M. (2016). Towards resolving strongly-interacting dark sectors at colliders. Physical Review D, 94(5), Article 055028. https://doi.org/10.1103/physrevd.94.055028

Dark sectors with strong interactions have received considerable interest. Assuming the existence of a minimally coupled dark sector which runs to strong interactions in the infrared, we address the question whether the scaling behavior of this dark... Read More about Towards resolving strongly-interacting dark sectors at colliders.

Measuring rare and exclusive Higgs boson decays into light resonances (2016)
Journal Article
Chisholm, A. S., Kuttimalai, S., Nikolopoulos, K., & Spannowsky, M. (2016). Measuring rare and exclusive Higgs boson decays into light resonances. The European Physical Journal C, 76(9), Article 501. https://doi.org/10.1140/epjc/s10052-016-4345-9

We evaluate the LHC’s potential of observing Higgs boson decays into light elementary or composite resonances through their hadronic decay channels. We focus on the Higgs boson production processes with the largest cross sections, pp→h pp→h and pp→h+... Read More about Measuring rare and exclusive Higgs boson decays into light resonances.

Cosmic ray air showers from sphalerons (2016)
Journal Article
Brooijmans, G., Schichtel, P., & Spannowsky, M. (2016). Cosmic ray air showers from sphalerons. Physics Letters B, 761, 213-218. https://doi.org/10.1016/j.physletb.2016.08.030

The discovery of the Higgs boson marks a key ingredient to establish the electroweak structure of the Standard Model. Its non-abelian gauge structure gives rise to, yet unobserved, non-perturbative baryon and lepton number violating processes. We pro... Read More about Cosmic ray air showers from sphalerons.

Searching for supersymmetry scalelessly (2016)
Journal Article
Schlaffer, M., Spannowsky, M., & Weiler, A. (2016). Searching for supersymmetry scalelessly. The European Physical Journal C, 76(8), Article 457. https://doi.org/10.1140/epjc/s10052-016-4299-y

In this paper we propose a scale invariant search strategy for hadronic top or bottom plus missing energy final states. We present a method which shows flat efficiencies and background rejection factors over broad ranges of parameters and masses. The... Read More about Searching for supersymmetry scalelessly.

Cornering diphoton resonance models at the LHC (2016)
Journal Article
Backović, M., Kulkarni, S., Mariotti, A., Sessolo, E. M., & Spannowsky, M. (2016). Cornering diphoton resonance models at the LHC. Journal of High Energy Physics, 2016(08), Article 018. https://doi.org/10.1007/jhep08%282016%29018

We explore the ability of the high luminosity LHC to test models which can explain the 750 GeV diphoton excess. We focus on a wide class of models where a 750 GeV singlet scalar couples to Standard Model gauge bosons and quarks, as well as dark matte... Read More about Cornering diphoton resonance models at the LHC.

Determining the quantum numbers of simplified models in tt¯X production at the LHC (2016)
Journal Article
Dolan, M. J., Spannowsky, M., Wang, Q., & Yu, Z. (2016). Determining the quantum numbers of simplified models in tt¯X production at the LHC. Physical Review D, 94(1), Article 015025. https://doi.org/10.1103/physrevd.94.015025

Simplified models provide an avenue for characterizing and exploring new physics for large classes of UV theories. In this article we study the ability of the LHC to probe the spin and parity quantum numbers of a new light resonance X which couples p... Read More about Determining the quantum numbers of simplified models in tt¯X production at the LHC.

Higgs coupling measurements at the LHC (2016)
Journal Article
Englert, C., Kogler, R., Schulz, H., & Spannowsky, M. (2016). Higgs coupling measurements at the LHC. The European Physical Journal C, 76(7), Article 393. https://doi.org/10.1140/epjc/s10052-016-4227-1

Due to the absence of tantalising hints for new physics during the LHC’s Run 1, the extension of the Higgs sector by dimension-six operators will provide the new phenomenological standard for searches of non-resonant extensions of the Standard Model.... Read More about Higgs coupling measurements at the LHC.

The Lepton Flavour Violating Higgs Decays at the HL-LHC and the ILC (2016)
Journal Article
Banerjee, S., Bhattacherjee, B., Mitra, M., & Spannowsky, M. (2016). The Lepton Flavour Violating Higgs Decays at the HL-LHC and the ILC. Journal of High Energy Physics, 2016(07), Article 059. https://doi.org/10.1007/jhep07%282016%29059

Run-I results from the CMS collaboration show an excess of events in the decay h → μτe with a local significances of 2.4σ. This could be the first hint of flavour violation in the Higgs sector. We summarise the bounds on the flavour violating Yukawa... Read More about The Lepton Flavour Violating Higgs Decays at the HL-LHC and the ILC.

Identification of high transverse momentum top quarks in pp collisions at s√=8s=8 TeV with the ATLAS detector (2016)
Journal Article
Spannowsky, M., & collaboration, A. (2016). Identification of high transverse momentum top quarks in pp collisions at s√=8s=8 TeV with the ATLAS detector. Journal of High Energy Physics, 2016(06), Article 093. https://doi.org/10.1007/jhep06%282016%29093

This paper presents studies of the performance of several jet-substructure techniques, which are used to identify hadronically decaying top quarks with high transverse momentum contained in large-radius jets. The efficiency of identifying top quarks... Read More about Identification of high transverse momentum top quarks in pp collisions at s√=8s=8 TeV with the ATLAS detector.

New physics and signal-background interference in associated pp → HZ production (2016)
Journal Article
Englert, C., Rosenfeld, R., Spannowsky, M., & Tonero, A. (2016). New physics and signal-background interference in associated pp → HZ production. European Physical Society Letters, 114(3), Article 31001. https://doi.org/10.1209/0295-5075/114/31001

We re-investigate electroweak signal-background interference in associated Higgs production via gluon fusion in the presence of new physics in the top Higgs sector. Considering the full final state $pp \to b \bar b \ell^+\ell^-~(\ell=e,\mu)$ , we dis... Read More about New physics and signal-background interference in associated pp → HZ production.

Search for Sphalerons: IceCube vs. LHC (2016)
Journal Article
Ellis, J., Sakurai, K., & Spannowsky, M. (2016). Search for Sphalerons: IceCube vs. LHC. Journal of High Energy Physics, 2016(05), Article 085. https://doi.org/10.1007/jhep05%282016%29085

We discuss the observability of neutrino-induced sphaleron transitions in the IceCube detector, encouraged by a recent paper by Tye and Wong (TW), which argued on the basis of a Bloch wave function in the periodic sphaleron potential that such transi... Read More about Search for Sphalerons: IceCube vs. LHC.

Closing up on Dark Sectors at colliders: from 14 to 100 TeV (2016)
Journal Article
Harris, P., Khoze, V. V., Spannowsky, M., & Williams, C. (2016). Closing up on Dark Sectors at colliders: from 14 to 100 TeV. Physical Review D, 93(5), Article 054030. https://doi.org/10.1103/physrevd.93.054030

-channel) messenger fields: scalar, pseudoscalar, vector or axial-vector. Our analysis extends and updates the previously available results for the LHC at 8 and 14 TeV to 100 TeV for models with all four messenger types. We revisit and improve the an... Read More about Closing up on Dark Sectors at colliders: from 14 to 100 TeV.

Measuring the Higgs-bottom coupling in weak boson fusion (2016)
Journal Article
Englert, C., Mattelaer, O., & Spannowsky, M. (2016). Measuring the Higgs-bottom coupling in weak boson fusion. Physics Letters B, 756, 103-108. https://doi.org/10.1016/j.physletb.2016.02.074

We study Higgs production through weak boson fusion with subsequent decay to bottom quarks. By combining jet substructure techniques and matrix element methods in different limits we motivate this channel as a probe of the bottom-Yukawa interactions... Read More about Measuring the Higgs-bottom coupling in weak boson fusion.

Measuring the signal strength in tt¯HwithH→bb¯ (2016)
Journal Article
Moretti, N., Petrov, P., Pozzorini, S., & Spannowsky, M. (2016). Measuring the signal strength in tt¯HwithH→bb¯. Physical Review D, 93(1), Article 014019. https://doi.org/10.1103/physrevd.93.014019

A precise measurement of the Higgs boson couplings to bottom and top quarks is of paramount importance during the upcoming LHC runs. We present a comprehensive analysis for the Higgs production process in association with a semileptonically decaying... Read More about Measuring the signal strength in tt¯HwithH→bb¯.

Probing MeV to 90 GeV axion-like particles with LEP and LHC (2015)
Journal Article
Jaeckel, J., & Spannowsky, M. (2016). Probing MeV to 90 GeV axion-like particles with LEP and LHC. Physics Letters B, 753, 482-487. https://doi.org/10.1016/j.physletb.2015.12.037

Axion-like particles (ALPs), relatively light (pseudo-)scalars coupled to two gauge bosons, are a common feature of many extensions of the Standard Model. Up to now there has been a gap in the sensitivity to such particles in the MeV to 10 GeV range.... Read More about Probing MeV to 90 GeV axion-like particles with LEP and LHC.

Combining LEP and LHC to bound the Higgs Width (2015)
Journal Article
Englert, C., McCullough, M., & Spannowsky, M. (2016). Combining LEP and LHC to bound the Higgs Width. Nuclear Physics B, 902, 440-457. https://doi.org/10.1016/j.nuclphysb.2015.11.017

The correlation of on- and off-shell Higgs boson production at the LHC in gg→h⁎→ZZgg→h⁎→ZZ has been used to bound the Higgs width. We propose an alternative complementary constraint which is only possible through the combination of LEP and LHC measur... Read More about Combining LEP and LHC to bound the Higgs Width.

Probing a light CP-odd scalar in di-top-associated production at the LHC (2015)
Journal Article
Casolino, M., Farooque, T., Juste, A., Liu, T., & Spannowsky, M. (2015). Probing a light CP-odd scalar in di-top-associated production at the LHC. The European Physical Journal C, 75, Article 498. https://doi.org/10.1140/epjc/s10052-015-3708-y

CP-odd scalars are an integral part of many extensions of the Standard Model. Recently, electroweak-scale pseudoscalars have received increased attention in explaining the diffuse gamma-ray excess from the Galactic Centre. Elusive due to absence of d... Read More about Probing a light CP-odd scalar in di-top-associated production at the LHC.

Spectroscopy of scalar mediators to dark matter at the LHC and at 100 TeV (2015)
Journal Article
Khoze, V. V., Ro, G., & Spannowsky, M. (2015). Spectroscopy of scalar mediators to dark matter at the LHC and at 100 TeV. Physical Review D, 92(7), Article 075006. https://doi.org/10.1103/physrevd.92.075006

We investigate simplified models of dark matter with scalar mediators at hadron colliders using the final state topology with two jets and missing energy. These models can arise in a wide variety of BSM scenarios including the possibility of the medi... Read More about Spectroscopy of scalar mediators to dark matter at the LHC and at 100 TeV.

Augmenting the diboson excess for the LHC Run II (2015)
Journal Article
Gonçalves, D., Krauss, F., & Spannowsky, M. (2015). Augmenting the diboson excess for the LHC Run II. Physical Review D, 92(5), https://doi.org/10.1103/physrevd.92.053010

The ATLAS collaboration recently reported an excess of events in the high invariant mass tail of reconstructed diboson events. We investigate their analysis and point to possible subtleties and improvements in the jet substructure implementation and... Read More about Augmenting the diboson excess for the LHC Run II.

Towards an Understanding of the Correlations in Jet Substructure (2015)
Journal Article
Adams, D., Arce, A., Asquith, L., Backovic, M., Barillari, T., Berta, P., …Young, C. (2015). Towards an Understanding of the Correlations in Jet Substructure. The European Physical Journal C, 75(9), Article 409. https://doi.org/10.1140/epjc/s10052-015-3587-2

Over the past decade, a large number of jet substructure observables have been proposed in the literature, and explored at the LHC experiments. Such observables attempt to utilize the internal structure of jets in order to distinguish those initiated... Read More about Towards an Understanding of the Correlations in Jet Substructure.

Unitarity-controlled resonances after the Higgs boson discovery (2015)
Journal Article
Englert, C., Harris, P., Spannowsky, M., & Takeuchi, M. (2015). Unitarity-controlled resonances after the Higgs boson discovery. Physical Review D, 92(1), Article 013003. https://doi.org/10.1103/physrevd.92.013003

If the recently discovered Higgs boson’s couplings deviate from the Standard Model expectation, we may anticipate new resonant physics in the weak boson fusion channels resulting from high scale unitarity sum rules of longitudinal gauge boson scatter... Read More about Unitarity-controlled resonances after the Higgs boson discovery.

Signs of Tops from Highly Mixed Stops (2015)
Journal Article
Backović, M., Mariotti, A., & Spannowsky, M. (2015). Signs of Tops from Highly Mixed Stops. Journal of High Energy Physics, 2015(06), Article 122. https://doi.org/10.1007/jhep06%282015%29122

Supersymmetric extensions of the Standard Model with highly mixed squark flavours beyond minimal flavour violation provide interesting scenarios of new physics, which have so far received limited attention. We propose a calculable realization of such... Read More about Signs of Tops from Highly Mixed Stops.

Off-Shell Higgs Coupling Measurements in BSM scenarios (2015)
Journal Article
Englert, C., Soteq, Y., & Spannowsky, M. (2015). Off-Shell Higgs Coupling Measurements in BSM scenarios. Journal of High Energy Physics, 2015(05), Article 145. https://doi.org/10.1007/jhep05%282015%29145

Proposals of measuring the off-shell Higgs contributions and first measurements at the LHC have electrified the Higgs phenomenology community for two reasons: firstly, probing interactions at high invariant masses and momentum transfers is intrinsica... Read More about Off-Shell Higgs Coupling Measurements in BSM scenarios.

On-shell interference effects in Higgs boson final states (2015)
Journal Article
Englert, C., Low, I., & Spannowsky, M. (2015). On-shell interference effects in Higgs boson final states. Physical Review D, 91(7), Article 074029. https://doi.org/10.1103/physrevd.91.074029

Top quark loops in Higgs production via gluon fusion at large invariant final state masses can induce important interference effects in searches for additional Higgs bosons as predicted in, e.g., Higgs portal scenarios and the minimal supersymmetric... Read More about On-shell interference effects in Higgs boson final states.

Constraining Dark Sectors at Colliders: Beyond the Effective Theory Approach (2015)
Journal Article
Harris, P., Khoze, V. V., Spannowsky, M., & Williams, C. (2015). Constraining Dark Sectors at Colliders: Beyond the Effective Theory Approach. Physical Review D, 91(5), https://doi.org/10.1103/physrevd.91.055009

We outline and investigate a set of benchmark simplified models with the aim of providing a minimal simple framework for an interpretation of the existing and forthcoming searches of dark matter particles at the LHC. The simplified models we consider... Read More about Constraining Dark Sectors at Colliders: Beyond the Effective Theory Approach.

Di-Higgs phenomenology in t¯thh: The forgotten channel (2015)
Journal Article
Englert, C., Krauss, F., Spannowsky, M., & Thompson, J. (2015). Di-Higgs phenomenology in t¯thh: The forgotten channel. Physics Letters B, 743, 93-97. https://doi.org/10.1016/j.physletb.2015.02.041

Searches for multi-Higgs final states allow to constrain parameters of the SM (or extensions thereof) that directly relate to the mechanism of electroweak symmetry breaking. Multi-Higgs production cross sections, however, are small and the phenomenol... Read More about Di-Higgs phenomenology in t¯thh: The forgotten channel.

Higgs Self-Coupling Measurements at a 100 TeV Hadron Collider (2015)
Journal Article
Barr, A. J., Dolan, M. J., Englert, C., Ferreira de Lima, D. E., & Spannowsky, M. (2015). Higgs Self-Coupling Measurements at a 100 TeV Hadron Collider. Journal of High Energy Physics, 2015(02), Article 016. https://doi.org/10.1007/jhep02%282015%29016

An important physics goal of a possible next-generation high-energy hadron collider will be precision characterisation of the Higgs sector and electroweak symmetry breaking. A crucial part of understanding the nature of electroweak symmetry breaking... Read More about Higgs Self-Coupling Measurements at a 100 TeV Hadron Collider.

Scattering of Dark Particles with Light Mediators (2014)
Journal Article
Soper, D. E., Spannowsky, M., Wallace, C., & Tait, T. M. (2014). Scattering of Dark Particles with Light Mediators. Physical Review D, 90(11), Article 115005. https://doi.org/10.1103/physrevd.90.115005

We present a treatment of the high energy scattering of dark Dirac fermions from nuclei, mediated by the exchange of a light vector boson. The dark fermions are produced by proton-nucleus interactions in a fixed target and, after traversing shielding... Read More about Scattering of Dark Particles with Light Mediators.

Effective Theories and Measurements at Colliders (2014)
Journal Article
Englert, C., & Spannowsky, M. (2015). Effective Theories and Measurements at Colliders. Physics Letters B, 740, 8-15. https://doi.org/10.1016/j.physletb.2014.11.035

If the LHC run 2 will not provide conclusive hints for new resonant Physics beyond the Standard Model, dedicated and consistent search strategies at high momentum transfers will become the focus of searches for anticipated deviations from the Standar... Read More about Effective Theories and Measurements at Colliders.

Boosted Higgs Shapes (2014)
Journal Article
Schlaffer, M., Spannowsky, M., Takeuchi, M., Weiler, A., & Wymant, C. (2014). Boosted Higgs Shapes. The European Physical Journal C, 74(10), https://doi.org/10.1140/epjc/s10052-014-3120-z

The inclusive Higgs production rate through gluon fusion has been measured to be in agreement with the Standard Model (SM). We show that even if the inclusive Higgs production rate is very SM-like, a precise determination of the boosted Higgs transve... Read More about Boosted Higgs Shapes.

Constraining CP-violating Higgs sectors at the LHC using gluon fusion (2014)
Journal Article
Dolan, M. J., Harris, P., Jankowiak, M., & Spannowsky, M. (2014). Constraining CP-violating Higgs sectors at the LHC using gluon fusion. Physical Review D, 90(7), Article 073008. https://doi.org/10.1103/physrevd.90.073008

We investigate the constraints that the LHC can set on a 126 GeV Higgs boson that is an admixture of CP eigenstates. Traditional analyses rely on Higgs couplings to massive vector bosons, which are suppressed for CP-odd couplings, so that these analy... Read More about Constraining CP-violating Higgs sectors at the LHC using gluon fusion.

Reconstructing singly produced top partners in decays to Wb (2014)
Journal Article
Gutierrez Ortiz, N., Ferrando, J., Kar, D., & Spannowsky, M. (2014). Reconstructing singly produced top partners in decays to Wb. Physical Review D, 90(7), Article 075009. https://doi.org/10.1103/physrevd.90.075009

Fermionic top partners are a feature of many models of physics beyond the standard model. We propose a search strategy for single production of top partners focusing specifically on the dominant decay to Wb . The enormous background can be reduced by... Read More about Reconstructing singly produced top partners in decays to Wb.

Limitations and opportunities of off-shell coupling measurements (2014)
Journal Article
Englert, C., & Spannowsky, M. (2014). Limitations and opportunities of off-shell coupling measurements. Physical Review D, 90(5), Article 053003. https://doi.org/10.1103/physrevd.90.053003

Indirect constraints on the total Higgs width Γh from correlating Higgs signal strengths with cross-section measurements in the off-shell region for p(g)p(g)→4ℓ production have received considerable attention recently, and the CMS Collaboration have... Read More about Limitations and opportunities of off-shell coupling measurements.

Standard model Higgs boson pair production in the ( bb¯ )( bb¯ ) final state (2014)
Journal Article
Ferreira de Lima, D., Papaefstathiou, A., & Spannowsky, M. (2014). Standard model Higgs boson pair production in the ( bb¯ )( bb¯ ) final state. Journal of High Energy Physics, 2014(8), Article 030. https://doi.org/10.1007/jhep08%282014%29030

Measuring the Higgs boson couplings as precisely as possible is one of the major goals of the High Luminosity LHC. We show that the ( bb ¯ )( bb ¯ ) final state in Higgs boson pair production can be exploited in the boosted regime to give constraints... Read More about Standard model Higgs boson pair production in the ( bb¯ )( bb¯ ) final state.

Resolving the Higgs-gluon coupling with jets (2014)
Journal Article
Buschmann, M., Englert, C., Goncalvec, D., Plehn, T., & Spannowsky, M. (2014). Resolving the Higgs-gluon coupling with jets. Physical Review D, 90(1), Article 013010. https://doi.org/10.1103/physrevd.90.013010

In the Standard Model, the Higgs coupling to gluons is almost entirely induced by top quark loops. We derive the logarithmic structure of Higgs production in association with two jets. Just like in the one-jet case, the transverse momentum distributi... Read More about Resolving the Higgs-gluon coupling with jets.

Dark Sector spectroscopy at the ILC (2014)
Journal Article
Andersen, J. R., Rauch, M., & Spannowsky, M. (2014). Dark Sector spectroscopy at the ILC. The European Physical Journal C, 74(6), Article 2908. https://doi.org/10.1140/epjc/s10052-014-2908-1

Recent studies have shown that searches in the mono-photon and missing energy final state can be used to discover dark matter candidates at the ILC. While an excess in this final state over the Standard Model background would indicate the existence o... Read More about Dark Sector spectroscopy at the ILC.

Measuring collinear W emissions inside jets (2014)
Journal Article
Krauss, F., Petrov, P., Schönherr, M., & Spannowsky, M. (2014). Measuring collinear W emissions inside jets. Physical Review D, 89(11), Article 114006. https://doi.org/10.1103/physrevd.89.114006

Single and multiple emission of electroweak gauge bosons and in particular of W bosons is discussed in the parton shower language. Algorithms and observables for the reconstruction of both leptonically and hadronically decaying W bosons inside light... Read More about Measuring collinear W emissions inside jets.

Extended gamma-ray emission from Coy Dark Matter (2014)
Journal Article
Bœhm, C., Dolan, M. J., McCabe, C., & Spannowsky, M. (2014). Extended gamma-ray emission from Coy Dark Matter. Journal of Cosmology and Astroparticle Physics, 2014(05), Article 009. https://doi.org/10.1088/1475-7516/2014/05/009

We show that it is possible for WIMP dark matter to produce a large signal in indirect dark matter searches without producing signals elsewhere. We illustrate our point by fitting the Fermi-LAT extended galactic gamma-ray excess with a simple model o... Read More about Extended gamma-ray emission from Coy Dark Matter.

Finding physics signals with event deconstruction (2014)
Journal Article
Soper, D. E., & Spannowsky, M. (2014). Finding physics signals with event deconstruction. Physical Review D, 89(9), Article 094005. https://doi.org/10.1103/physrevd.89.094005

We develop a matrix element based reconstruction method called event deconstruction. The method uses information from the hard matrix element and a parton shower to assign probabilities to whether a final state was initiated by a signal or background... Read More about Finding physics signals with event deconstruction.

Nonstandard top substructure (2014)
Journal Article
Englert, C., Gonçalves, D., & Spannowsky, M. (2014). Nonstandard top substructure. Physical Review D, 89(7), Article 074038. https://doi.org/10.1103/physrevd.89.074038

The top quark, being the heaviest particle of the Standard Model (SM), is a prime candidate of where physics beyond the SM (BSM) might currently hide before our eyes. There are many natural extensions of the SM that rely on top compositeness, and the... Read More about Nonstandard top substructure.

Boosting Top Partner Searches in Composite Higgs Models (2014)
Journal Article
Azatov, A., Salvarezza, M., Son, M., & Spannowsky, M. (2014). Boosting Top Partner Searches in Composite Higgs Models. Physical Review D, 89(7), Article 075001. https://doi.org/10.1103/physrevd.89.075001

Fermionic third generation top partners are generic in composite Higgs models. They are likely to decay into third generation quarks and electroweak bosons. We propose a novel cut-and-count-style analysis in which we cross correlate the model-depende... Read More about Boosting Top Partner Searches in Composite Higgs Models.

Boosted objects and jet substructure at the LHC. Report of BOOST2012, held at IFIC Valencia, 23rd–27th of July 2012 (2014)
Journal Article
Altheimer, A., Arce, A., Asquith, L., Spannowsky, M., & et al. (2014). Boosted objects and jet substructure at the LHC. Report of BOOST2012, held at IFIC Valencia, 23rd–27th of July 2012. The European Physical Journal C, 74(3), Article 2792. https://doi.org/10.1140/epjc/s10052-014-2792-8

This report of the BOOST2012 workshop presents the results of four working groups that studied key aspects of jet substructure. We discuss the potential of first-principle QCD calculations to yield a precise description of the substructure of jets an... Read More about Boosted objects and jet substructure at the LHC. Report of BOOST2012, held at IFIC Valencia, 23rd–27th of July 2012.

Production of hhjj at the LHC (2014)
Journal Article
Dolan, M. J., Englert, C., Greiner, N., & Spannowsky, M. (2014). Production of hhjj at the LHC. Physical Review Letters, 112(10), Article 101802. https://doi.org/10.1103/physrevlett.112.101802

Until now, a phenomenologically complete analysis of the hh+2j channel at the LHC has been missing. This is mostly due to the high complexity of the involved one-loop gluon fusion contribution and the fact that a reliable estimate thereof cannot be o... Read More about Production of hhjj at the LHC.

Gluon-initiated associated production boosts Higgs physics (2014)
Journal Article
Englert, C., McCullough, M., & Spannowsky, M. (2014). Gluon-initiated associated production boosts Higgs physics. Physical Review D, 89(1), Article 013013. https://doi.org/10.1103/physrevd.89.013013

Analyses of boosted Higgs bosons from associated production comprise some of the main search channels for the Higgs boson at the LHC. The gluon-initiated gg→hZ subprocess has largely been ignored in phenomenological analyses of boosted associated pro... Read More about Gluon-initiated associated production boosts Higgs physics.

Tagging highly boosted top quarks (2014)
Journal Article
Schätzel, S., & Spannowsky, M. (2014). Tagging highly boosted top quarks. Physical Review D, 89(1), Article 014007. https://doi.org/10.1103/physrevd.89.014007

For highly energetic top quarks, the products of the decay t→bqq ′ are collimated. The three-prong decay structure can no longer be resolved using calorimeter information alone if the particle jet separation approaches the calorimeter granularity. We... Read More about Tagging highly boosted top quarks.

Di-Higgs final states augMT2ed – Selecting hh events at the high luminosity LHC (2013)
Journal Article
Barr, A. J., Dolan, M. J., Englert, C., & Spannowsky, M. (2014). Di-Higgs final states augMT2ed – Selecting hh events at the high luminosity LHC. Physics Letters B, 728, 308-313. https://doi.org/10.1016/j.physletb.2013.12.011

Higgs boson self-interactions can be investigated via di-Higgs (pp→hh+X) production at the LHC. With a small O(30) fb Standard Model production cross section, and a large View the MathML source background, this measurement has been considered challen... Read More about Di-Higgs final states augMT2ed – Selecting hh events at the high luminosity LHC.

LHC probes the hidden sector (2013)
Journal Article
Jaeckel, J., Jankowiak, M., & Spannowsky, M. (2013). LHC probes the hidden sector. Physics of the Dark Universe, 2(3), 111-117. https://doi.org/10.1016/j.dark.2013.06.001

In this note we establish LHC limits on a variety of benchmark models for hidden sector physics using 2011 and 2012 data. First, we consider a “hidden’’ U(1) gauge boson under which all Standard Model particles are uncharged at tree-level and which i... Read More about LHC probes the hidden sector.

Pinning down Higgs triplets at the LHC (2013)
Journal Article
Englert, C., Re, E., & Spannowsky, M. (2013). Pinning down Higgs triplets at the LHC. Physical Review D, 88(3), Article 035024. https://doi.org/10.1103/physrevd.88.035024

Extensions of the standard model Higgs sector involving weak isotriplet scalars are not only benchmark candidates to reconcile observed anomalies of the recently discovered Higgs-like particle, but also exhibit a vast parameter space, for which the l... Read More about Pinning down Higgs triplets at the LHC.

The shape of spins (2013)
Journal Article
Englert, C., Gonçalves, D., Nail, G., & Spannowsky, M. (2013). The shape of spins. Physical Review D, 88(1), Article 013016. https://doi.org/10.1103/physrevd.88.013016

After the discovery of a Higgs-like particle at the LHC, the determination of its spin quantum numbers across different channels will be the next step in arriving at a more precise understanding of the new state and its role in electroweak symmetry b... Read More about The shape of spins.

Triplet Higgs boson collider phenomenology after the LHC (2013)
Journal Article
Englert, C., Re, E., & Spannowsky, M. (2013). Triplet Higgs boson collider phenomenology after the LHC. Physical Review D, 87(9), Article 095014. https://doi.org/10.1103/physrevd.87.095014

ATLAS and CMS have discovered a standard model (SM) Higgs-like particle. One of the main discovery channels is the Higgs decay to two photons, which, at the moment, seems to be considerably enhanced over the standard model expectation. Models with ad... Read More about Triplet Higgs boson collider phenomenology after the LHC.

Emergence of the electroweak scale through the Higgs portal (2013)
Journal Article
Englert, C., Jaeckel, J., Khoze, V., & Spannowsky, M. (2013). Emergence of the electroweak scale through the Higgs portal. Journal of High Energy Physics, 2013(4), Article 60. https://doi.org/10.1007/jhep04%282013%29060

Having discovered a candidate for the final piece of the Standard Model, the Higgs boson, the question remains why its vacuum expectation value and its mass are so much smaller than the Planck scale (or any other high scale of new physics). One elega... Read More about Emergence of the electroweak scale through the Higgs portal.

Making the most of missing transverse energy: Mass reconstruction from collimated decays (2013)
Journal Article
Spannowsky, M., & Wymant, C. (2013). Making the most of missing transverse energy: Mass reconstruction from collimated decays. Physical Review D, 87(7), Article 074004. https://doi.org/10.1103/physrevd.87.074004

At hadron colliders invisible particles χ can be inferred only through observation of the transverse component of the vectorial sum of their momenta—missing ET or missing transverse energy (MET)—preventing reconstruction of the masses of their mother... Read More about Making the most of missing transverse energy: Mass reconstruction from collimated decays.

Finding top quarks with shower deconstruction (2013)
Journal Article
Soper, D. E., & Spannowsky, M. (2013). Finding top quarks with shower deconstruction. Physical Review D, 87(5), Article 054012. https://doi.org/10.1103/physrevd.87.054012

We develop a new method for tagging jets produced by hadronically decaying top quarks. The method is an application of shower deconstruction, a maximum information approach that was previously applied to identifying jets produced by Higgs bosons that... Read More about Finding top quarks with shower deconstruction.

New Physics in LHC Higgs boson pair production (2013)
Journal Article
Dolan, M. J., Englert, C., & Spannowsky, M. (2013). New Physics in LHC Higgs boson pair production. Physical Review D, 87(5), Article 055002. https://doi.org/10.1103/physrevd.87.055002

Multi-Higgs production provides a phenomenologically clear window to the electroweak symmetry-breaking sector. We perform a comprehensive and comparative analysis of new electroweak physics effects in di-Higgs and di−Higgs+jet production. In particul... Read More about New Physics in LHC Higgs boson pair production.

Extracting precise Higgs couplings by using the matrix element method (2013)
Journal Article
Andersen, J., Englert, C., & Spannowsky, M. (2013). Extracting precise Higgs couplings by using the matrix element method. Physical Review D, 87(1), Article 015019. https://doi.org/10.1103/physrevd.87.015019

After the recent discovery of a Standard Model Higgs bosonlike particle at the LHC, the question of its couplings to known and unknown matter is eminent. In this paper, we present a method that allows for an enhancement in signal over background (irr... Read More about Extracting precise Higgs couplings by using the matrix element method.

Jet Substructure at the Tevatron and LHC: New results, new tools, new benchmarks (2012)
Journal Article
al, A. E., & Spannowsky, M. (2012). Jet Substructure at the Tevatron and LHC: New results, new tools, new benchmarks. Journal of Physics G: Nuclear and Particle Physics, 39(6), Article 063001. https://doi.org/10.1088/0954-3899/39/6/063001

In this paper, we review recent theoretical progress and the latest experimental results in jet substructure from the Tevatron and the LHC. We review the status of and outlook for calculation and simulation tools for studying jet substructure. Follow... Read More about Jet Substructure at the Tevatron and LHC: New results, new tools, new benchmarks.

Evasive Higgs Boson Maneuvers at the LHC (2012)
Journal Article
Englert, C., Jaeckel, J., Re, E., & Spannowsky, M. (2012). Evasive Higgs Boson Maneuvers at the LHC. Physical Review D, Particles and fields, 85(3), Article 035008. https://doi.org/10.1103/physrevd.85.035008

Nonstandard decays of the Higgs boson produced at the Large Hadron Collider can lead to signatures which can easily be missed due to nonadapted trigger or search strategies. Keeping electroweak symmetry breaking standard model-like, we classify the p... Read More about Evasive Higgs Boson Maneuvers at the LHC.

AtFB meets LHC (2011)
Journal Article
Hewett, J. L., Shelton, J., Spannowsky, M., Tait, T. M., & Takeuchi, M. (2011). AtFB meets LHC. Physical Review D, 84(5), Article 054005. https://doi.org/10.1103/physrevd.84.054005

The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large tt̅ invariant masses. Measurements of this quantity are subtle at the LHC, due... Read More about AtFB meets LHC.

Discovering the Higgs Boson in New Physics Events using Jet Substructure (2010)
Journal Article
Kribs, G. D., Martin, A., Roy, T. S., & Spannowsky, M. (2010). Discovering the Higgs Boson in New Physics Events using Jet Substructure. Physical Review D, 81(11), Article 111501. https://doi.org/10.1103/physrevd.81.111501

We demonstrate that the Higgs boson can be discovered at the large hadron collider in new physics events using boosted kinematics, b-tagging and jet substructure. This method superbly identifies the lightest Higgs boson in the minimal supersymmetric... Read More about Discovering the Higgs Boson in New Physics Events using Jet Substructure.

hhjj production at the LHC (1999)
Journal Article
Dolan, M. J., Englert, C., Greiner, N., Nordstrom, K., & Spannowsky, M. (1999). hhjj production at the LHC. The European Physical Journal C, 75(8), Article 387. https://doi.org/10.1140/epjc/s10052-015-3622-3

The search for di-Higgs production at the LHC in order to set limits on the Higgs trilinear coupling and constraints on new physics is one of the main motivations for the LHC high-luminosity phase. Recent experimental analyses suggest that such analy... Read More about hhjj production at the LHC.