Higgs characterisation in the presence of theoretical uncertainties and invisible decays

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

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While the Higgs characterisation programme is well underway, 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→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 κ framework, we show explicitly that this method does not provide complementary sensitivity for scale-separated new physics Λ≫mh≫mϕ, which is favoured in beyond the Standard Model scenarios that relate astrophysics and collider phenomenology in light of non-observation of new physics during run 1 of the LHC.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Englert, Professor Christoph and Schulz, Dr Holger
Authors: Englert, C., Kogler, R., Schulz, H., and Spannowsky, M.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:European Physical Journal C
ISSN (Online):1434-6052
Published Online:21 November 2017
Copyright Holders:Copyright © 2017 The Authors
First Published:First published in European Physical Journal C 77:789
Publisher Policy:Reproduced under a Creative Commons License

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