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arXiv · 2312.12384

Interference Effects in $\mathbf{gg \to H \to Z γ}$ Beyond Leading Order

Federico Buccioni·Federica Devoto·Abdelhak Djouadi·John Ellis·Jérémie Quevillon·Lorenzo Tancredi
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Abstract

The ATLAS and CMS collaborations at the LHC have recently announced evidence for the rare Higgs boson decay into a $Z$ boson and a photon. We analyze the interference between the process $gg\! \to \! H \! \to \! Z γ$ induced by loops of heavy particles, which is by far the dominant contribution to the signal, and the continuum $gg \to Z γ$ QCD background process mediated by light quark loops. This interference modifies the event yield, the resonance line-shape and the apparent mass of the Higgs boson. We calculate the radiative corrections to this interference beyond the leading-order approximation in perturbative QCD and find that, while differing numerically from the corresponding effects on the more studied $gg \! \to \! γγ$ signal, they are generally rather small. As such, they do not impact significantly the interpretation of the present measurements of the $H \to Z γ$ decay mode.

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Federico Buccioni, Federica Devoto, Abdelhak Djouadi, John Ellis, Jérémie Quevillon, Lorenzo Tancredi. 2024-03-28. Interference Effects in $\mathbf{gg \to H \to Z γ}$ Beyond Leading Order. https://arxiv.org/abs/2312.12384

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