2026/08/04 by ATLAS Collaboration
Physics and Astronomy · #hep-ex
45 pages in total, author list starting page 28, 7 figures, 3 tables, submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGP-2024-16/
arxiv created 2026/08/04 · arxiv updated 2026/08/05
A measurement is presented for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ < 30 GeV, using pp collision data at √(s) = 13.6 TeV recorded by the ATLAS detector at the Large Hadron Collider during the years 2022-2024, corresponding to an integrated luminosity of 164 fb-1. The best-fit value of the signal strength parameter, defined as the ratio of the observed signal yield to the one expected in the Standard Model, is measured to be μ= 0.64+0.44-0.39 compared with the expected value of μ= 1.00+0.47-0.41. The corresponding observed (expected) signal significance is 1.7 (2.5) standard deviations under the background-only hypothesis. The result is combined with a similar search performed using 139 fb-1 of pp collision data at √(s) = 13 TeV collected during the years 2015-2018. This combination gives an observed (expected) signal strength of μ= 1.03+0.35-0.32 (μ= 1.00+0.34-0.32), corresponding to an observed (expected) significance of 3.4 (3.3) standard deviations.