Higgs characterisation in the presence of theoretical uncertainties and invisible decays

Englert, Christoph; Kogler, Roman; Schulz, Holger; Spannowsky, Michael

Abstract

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 effective operators, we discuss the extent to which theoretical uncertainties can limit the sensitivity in such a new physics search programme. Extending the dimension-6 Higgs Effective Field Theory framework by introducing new light degrees of freedom that can contribute to an invisible (or undetectable) Higgs decay width h→ϕϕh→ϕϕ , we show how differential coupling fits can disentangle effects from non-Standard Model couplings and an invisible decay width, as present in many new physics scenarios, such as Higgs-portal dark matter. Including the so-called off-shell measurement that has been advocated as a sensitive determination of the Higgs width in the κκ framework, we show explicitly that this method does not provide complementary sensitivity for scale-separated new physics Λ≫mh≫mϕΛ≫mh≫mϕ , which is favoured in beyond the Standard Model scenarios that relate astrophysics and collider phenomenology in the light of non-observation of new physics during run 1 of the LHC.

Citation

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

• Journal Article Type: Article
• Acceptance Date: Nov 4, 2017
• Online Publication Date: Nov 21, 2017
• Publication Date: Nov 21, 2017
• Deposit Date: Dec 13, 2017
• Publicly Available Date: Dec 13, 2017
• Journal: European Physical Journal C: Particles and Fields
• Print ISSN: 1434-6044
• Electronic ISSN: 1434-6052
• Publisher: SpringerOpen
• Peer Reviewed: Peer Reviewed
• Volume: 77
• Issue: 11
• Article Number: 789
• DOI: https://doi.org/10.1140/epjc/s10052-017-5366-8
• Public URL: https://durham-repository.worktribe.com/output/1342380