Regular Article - Theoretical Physics
Signal-background interference effects in Higgs-mediated diphoton production beyond NLO
Rudolf Peierls Centre for Theoretical Physics, University of Oxford, Clarendon Laboratory, Parks Road, OX1 3PU, Oxford, UK
2 Physics Department, Technical University of Munich, James-Franck-Straße 1, 85748, Garching, Germany
3 Department of Physics and Astronomy, Michigan State University, 48824, East Lansing, MI, USA
Accepted: 13 February 2023
Published online: 23 February 2023
In this paper we consider signal-background interference effects in Higgs-mediated diphoton production at the LHC. After reviewing earlier works that show how to use these effects to constrain the Higgs boson total decay width, we provide predictions beyond NLO accuracy for the interference and related observables, and study the impact of QCD radiative corrections on the Higgs width determination. In particular, we use the so-called soft-virtual approximation to estimate interference effects at NNLO in QCD. The inclusion of these effects reduces the NNLO prediction for the total Higgs cross-section in the diphoton channel by about 1.7%. We study in detail the impact of QCD corrections on the Higgs-boson line-shape and its implications for the Higgs boson width extraction. In particular, we find that the shift of the Higgs resonance peak arising from interference effects gets reduced by about 30% with respect to the NLO prediction. Assuming an experimental resolution of about 150 on interference-induced modifications of the Higgs-boson line-shape, our NNLO analysis shows that one could constrain the Higgs-boson total width to about 10–20 times its Standard Model value.
© The Author(s) 2023
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