A search for the Higgs boson decay to a Z boson and a photon in the ℓℓ γ (ℓ=e,μ) final state is performed using pp collisions at s=13.6 TeV recorded with the ATLAS detector at the Large Hadron Collider during 2022–2024, corresponding to an integrated luminosity of 165 fb−1. The signal yield, normalised to the Standard Model prediction, is measured to be μ=0.9−0.6+0.7, compatible with the expected value of μ=1.0±0.7. This corresponds to an observed (expected) signal significance of 1.4 (1.5) standard deviations under the background-only hypothesis. This result is combined with that of a similar search performed with 140 fb−1 of s=13 TeV pp collisions to provide the best expected sensitivity to date to this rare decay, namely an observed (expected) signal strength of μ=1.3−0.5+0.6 (μ=1.0−0.5+0.6), corresponding to an observed (expected) significance of 2.5 (1.9) standard deviations. The measurement is consistent with the Standard Model expectation.

Search for the Higgs boson decay to a Z boson and a photon in pp collisions at s=13 TeV and 13.6 TeV with the ATLAS detector

Cobal M.;Giordani M. P.;Giugliarelli G.;Monzani S.;Panizzo G.;
2026-01-01

Abstract

A search for the Higgs boson decay to a Z boson and a photon in the ℓℓ γ (ℓ=e,μ) final state is performed using pp collisions at s=13.6 TeV recorded with the ATLAS detector at the Large Hadron Collider during 2022–2024, corresponding to an integrated luminosity of 165 fb−1. The signal yield, normalised to the Standard Model prediction, is measured to be μ=0.9−0.6+0.7, compatible with the expected value of μ=1.0±0.7. This corresponds to an observed (expected) signal significance of 1.4 (1.5) standard deviations under the background-only hypothesis. This result is combined with that of a similar search performed with 140 fb−1 of s=13 TeV pp collisions to provide the best expected sensitivity to date to this rare decay, namely an observed (expected) signal strength of μ=1.3−0.5+0.6 (μ=1.0−0.5+0.6), corresponding to an observed (expected) significance of 2.5 (1.9) standard deviations. The measurement is consistent with the Standard Model expectation.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11390/1332512
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