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Exclusive J/ψ and ϒ production in high-energy pp and p-Pb collisions (2022)
Journal Article
Flett, C., Jones, S., Martin, A., Ryskin, M., & Teubner, T. (2022). Exclusive J/ψ and ϒ production in high-energy pp and p-Pb collisions. Physical Review D, 106(7), https://doi.org/10.1103/physrevd.106.074021

We present a formalism for determining the cross section for exclusive heavy vector meson production (J/ψ,Υ) as a function of rapidity, in both high-energy proton-proton and proton-heavy ion collisions, at next-to-leading order in QCD. We compare and... Read More about Exclusive J/ψ and ϒ production in high-energy pp and p-Pb collisions.

Predictions of exclusive ϒ photoproduction at the LHC and future colliders (2022)
Journal Article
Flett, C., Jones, S., Martin, A., Ryskin, M., & Teubner, T. (2022). Predictions of exclusive ϒ photoproduction at the LHC and future colliders. Physical Review D, 105(3), https://doi.org/10.1103/physrevd.105.034008

The cross section for exclusive ϒ ultraperipheral photoproduction at present and future colliders is determined using the low x gluon parton distribution function extracted from an analysis of exclusive J=ψ measurements performed at the Hadron-Electr... Read More about Predictions of exclusive ϒ photoproduction at the LHC and future colliders.

QED parton distribution functions in the MSHT20 fit (2022)
Journal Article
Cridge, T., Harland-Lang, L., Martin, A., & Thorne, R. (2022). QED parton distribution functions in the MSHT20 fit. The European Physical Journal C, 82(1), Article 90. https://doi.org/10.1140/epjc/s10052-022-10028-2

We present the MSHT20qed set of parton distribution functions (PDFs). These are obtained from the MSHT20 global analysis via a refit including QED corrections to the DGLAP evolution at O(α),O(ααS) and O(α2), and containing the photon PDF of the proto... Read More about QED parton distribution functions in the MSHT20 fit.

An investigation of the $$\alpha _S$$ and heavy quark mass dependence in the MSHT20 global PDF analysis (2021)
Journal Article
Cridge, T., Harland-Lang, L., Martin, A., & Thorne, R. (2021). An investigation of the $$\alpha _S$$ and heavy quark mass dependence in the MSHT20 global PDF analysis. The European Physical Journal C, 81(8), Article 744. https://doi.org/10.1140/epjc/s10052-021-09533-7

We investigate the MSHT20 global PDF sets, demonstrating the effects of varying the strong coupling αS(M2Z) and the masses of the charm and bottom quarks. We determine the preferred value, and accompanying uncertainties, when we allow αS(M2Z) to be a... Read More about An investigation of the $$\alpha _S$$ and heavy quark mass dependence in the MSHT20 global PDF analysis.

Parton distributions from LHC, HERA, Tevatron and fixed target data: MSHT20 PDFs (2021)
Journal Article
Bailey, S., Cridge, T., Harland-Lang, L., Martin, A., & Thorne, R. (2021). Parton distributions from LHC, HERA, Tevatron and fixed target data: MSHT20 PDFs. The European Physical Journal C, 81(4), Article 341. https://doi.org/10.1140/epjc/s10052-021-09057-0

We present the new MSHT20 set of parton distribution functions (PDFs) of the proton, determined from global analyses of the available hard scattering data. The PDFs are made available at NNLO, NLO, and LO, and supersede the MMHT14 sets. They are obta... Read More about Parton distributions from LHC, HERA, Tevatron and fixed target data: MSHT20 PDFs.

Dynamics of diffractive dissociation (2021)
Journal Article
Khoze, V., Martin, A., & Ryskin, M. (2021). Dynamics of diffractive dissociation. The European Physical Journal C, 81(2), Article 175. https://doi.org/10.1140/epjc/s10052-021-08953-9

We describe a QCD based model which incorporates the main properties of the inclusive particle distributions expected for diffractive processes, including the diffractive dissociation at high energies. We study, in turn, the total cross section, σtot... Read More about Dynamics of diffractive dissociation.

Comments on Global Parton Analyses (2020)
Journal Article
Martin, A., & Ryskin, M. (2020). Comments on Global Parton Analyses. Acta Physica Polonica B, 51(5), 1079-1096. https://doi.org/10.5506/aphyspolb.51.1079

We discuss the causes which can limit the accuracy of the predictions based on the conventional PDFs when including in global parton analyses the data at moderate scales μ. The first is the existence of power corrections O(Q20/μ2) due to the double c... Read More about Comments on Global Parton Analyses.

Very low x gluon density determined by LHCb exclusive J/ψ data (2020)
Journal Article
Flett, C., Martin, A., Ryskin, M., & Teubner, T. (2020). Very low x gluon density determined by LHCb exclusive J/ψ data. Physical Review D, 102(11), Article 114021. https://doi.org/10.1103/physrevd.102.114021

The low x behavior of the gluon density x g ( x , μ 2 ) at scale μ 2 = 2.4     GeV 2 is determined using exclusive J / ψ production data from HERA and LHCb within the framework of collinear factorization at next-to-leading order (NLO). It is shown th... Read More about Very low x gluon density determined by LHCb exclusive J/ψ data.

How to include exclusive J/ψ production data in global PDF analyses (2020)
Journal Article
Flett, C., Jones, S., Martin, A., Ryskin, M., & Teubner, T. (2020). How to include exclusive J/ψ production data in global PDF analyses. Physical Review D, 101(9), Article 094011. https://doi.org/10.1103/physrevd.101.094011

We compare the cross section for exclusive J=ψ photoproduction calculated at next-to-leading order (NLO) in the collinear factorization approach with HERA and LHCb data. Using the optimum scale formalism together with the subtraction of the low kt co... Read More about How to include exclusive J/ψ production data in global PDF analyses.

Isolating the Odderon in central production in high energy pA and AA collisions (2020)
Journal Article
McNulty, R., Khoze, V., Martin, A., & Ryskin, M. (2020). Isolating the Odderon in central production in high energy pA and AA collisions. The European Physical Journal C, 80(3), Article 80. https://doi.org/10.1140/epjc/s10052-020-7846-5

We study the rapidity dependence of the central exclusive production cross sections of C-even mesons in pA and AA collisions, where A is a heavy ion. We observe qualitatively different behaviour of the contributions arising from γ-Odderon and Pomeron... Read More about Isolating the Odderon in central production in high energy pA and AA collisions.

Bethe phase including proton excitations (2020)
Journal Article
Khoze, V., Martin, A., & Ryskin, M. (2020). Bethe phase including proton excitations. Physical Review D, 101(1), Article 016018. https://doi.org/10.1103/physrevd.101.016018

We evaluate the contribution of inelastic intermediate states (such as p → N excitations) to the phase between the one-photon-exchange and the “nuclear” high energy pp scattering amplitudes as t → 0, caused by multiphoton diagrams. It turns out to be... Read More about Bethe phase including proton excitations.

Ad Lucem: QED parton distribution functions in the MMHT framework (2019)
Journal Article
Harland-Lang, L., Martin, A., Nathvani, R., & Thorne, R. (2019). Ad Lucem: QED parton distribution functions in the MMHT framework. The European Physical Journal C, 79(10), Article 811. https://doi.org/10.1140/epjc/s10052-019-7296-0

We present the MMHT2015qed PDF set, resulting from the inclusion of QED corrections to the existing set of MMHT Parton Distribution Functions (PDFs), and which contain the photon PDF of the proton. Adopting an input distribution from the LUXqed formu... Read More about Ad Lucem: QED parton distribution functions in the MMHT framework.

Colliding Pomerons (2019)
Journal Article
Khoze, V., Martin, A., & Ryskin, M. (2019). Colliding Pomerons. Journal of Physics G: Nuclear and Particle Physics, 46(11), Article 11LT01. https://doi.org/10.1088/1361-6471/ab3a88

We recall the main properties of inclusive particle distributions expected for Pomeron-proton and Pomeron–Pomeron interactions. Due to the small size of the Pomeron we expect larger transverse momenta of secondaries and a smaller probability of multi... Read More about Colliding Pomerons.

The fusion of hard and soft Pomerons: 3-jet diffractive production (2019)
Journal Article
Khoze, V., Martin, A., Ryskin, M., Shuvaev, A., & Surnin, I. (2019). The fusion of hard and soft Pomerons: 3-jet diffractive production. The European Physical Journal C, 79(7), Article 605. https://doi.org/10.1140/epjc/s10052-019-7120-x

We consider the central exclusive production of high E_T jets pp\rightarrow p+(X+\mathrm{dijet})+p. In particular we study the possible contamination of the purely exclusive signal by semi-exclusive production where no other secondaries are emitted i... Read More about The fusion of hard and soft Pomerons: 3-jet diffractive production.

Exclusive vector meson production in heavy ion collisions (2019)
Journal Article
Khoze, V., Martin, A., & Ryskin, M. (2019). Exclusive vector meson production in heavy ion collisions. Journal of Physics G: Nuclear and Particle Physics, 46(8), Article 085002. https://doi.org/10.1088/1361-6471/ab2009

We discuss the salient features of exclusive vector meson production in heavy ion collisions at LHC energies. Special attention is paid to the space-time picture of the process. We account for both coherent and incoherent contributions. The explicit... Read More about Exclusive vector meson production in heavy ion collisions.

Searching for the odderon in ultraperipheral proton-ion collisions at the LHC (2019)
Journal Article
Harland-Lang, L., Khoze, V., Martin, A., & Ryskin, M. (2019). Searching for the odderon in ultraperipheral proton-ion collisions at the LHC. Physical Review D, 99(3), Article 034011. https://doi.org/10.1103/physrevd.99.034011

We explore the possibility of observing odderon exchange in proton-ion collisions at the LHC, via the ultraperipheral photoproduction of C-even mesons. As well as the signal, we consider in detail the principle backgrounds, due to QCD-initiated produ... Read More about Searching for the odderon in ultraperipheral proton-ion collisions at the LHC.

Absorptive effects and power corrections in low x DGLAP evolution (2019)
Journal Article
Pelicer, M., de Oliveira, E., Martin, A., & Ryskin, M. (2019). Absorptive effects and power corrections in low x DGLAP evolution. The European Physical Journal C, 79(1), Article 9. https://doi.org/10.1140/epjc/s10052-018-6515-4

We address a long standing problem concerning the scale behaviour of parton densities in the low x, low Q2 domain. We emphasize the important role of absorptive corrections at low x and use knowledge of diffractive deep inelastic scattering to exclud... Read More about Absorptive effects and power corrections in low x DGLAP evolution.

MMHT Updates, LHC jets and α S (2018)
Presentation / Conference Contribution
Thorne, R., Harland-Lang, L., & Martin, A. (2018, December). MMHT Updates, LHC jets and α S. Presented at Proceedings of XXVI International Workshop on Deep-Inelastic Scattering and Related Subjects — PoS(DIS2018)

We summarise the effects of including jet data from the LHC in the MMHT PDF extraction. We also present the latest results on the preferred value of the strong coupling α S ( M 2 Z ) αS(MZ2) in a number of fit variations. The best current value with... Read More about MMHT Updates, LHC jets and α S.

Black disk radius constrained by unitarity (2018)
Journal Article
Khoze, V., Martin, A., & Ryskin, M. (2018). Black disk radius constrained by unitarity. Physics Letters B, 787, 167-170. https://doi.org/10.1016/j.physletb.2018.10.054

We argue that if the elastic proton–proton cross section increases with energy, the Froissart-like high energy behaviour of the elastic amplitude (which corresponds to a ‘black disk’ of radius R(s) = c ln s −βln(ln s)) is the only possibility to sati... Read More about Black disk radius constrained by unitarity.