Search for the Higgs boson decay to a <i>Z</i> boson and a photon in <i>pp </i>collisions at √<i>s</i> = 13 TeV and 13.6 TeV with the ATLAS detector
A search for the Higgs boson decay to a <i>Z </i>boson and a photon in the ℓℓ<i>γ</i> (ℓ = <i>e</i>, <i>μ</i>) final state is performed using <i>pp </i>collisions at √<i>s </i>= 13.6 TeV recorded with the ATLAS detector at the Large Hadron Collider during 2022-2024, corresponding to an integrated luminosity of 165 fb<sup>−1</sup>. The signal yield, normalised to the Standard Model prediction, is measured to be <i>μ</i> = 0.9<sup>+0.7</sup><sub>−0.6</sub>, compared to an expected value of <i>μ </i>= 1.0 ± 0.7. This corresponds to an observed (expected) signal significance of 1.4 (1.5) standard deviations for the background-only hypothesis. This result is combined with that of a similar search performed with 140 fb<sup>−1</sup> of √<i>s </i>= 13 TeV <i>pp</i> collisions to provide the most stringent expected sensitivity to date to this rare decay, namely an observed (expected) signal strength of <i>μ </i>= 1.3<sup>+0.6</sup><sub>−0.5</sub> (<i>μ </i>= 1.0<sup>+0.6</sup><sub>−0.5</sub>), corresponding to an observed (expected) significance of 2.5 (1.9) standard deviations. The measurement is consistent with the Standard Model expectation.
Authors
- L. Gonella
- E.H.L. Liu
- P.R. Newman
- J.P. Thomas
- A. Dimitrievska
- D.G.; id_orcid 0000-0003-0211-2041 Charlton
- A.S. Chisholm
- I. Benaoumeur
- P.D. Thompson
- P.P. Allport
- A.T. Watson
- T.J. Neep
- M.F. Watson
- C.M. Hawkes
- J. Bracinik
- J.D.; id_orcid 0000-0001-7456-494X Lomas
- P. Bellos
- F. Gonnella
- S.J.; id_orcid 0000-0002-7599-6469 Hillier
- K. Krizka
- E. Skorda
Publication Details
- Journal
- University of Birmingham Research Portal (University of Birmingham)
- Published
- 2026-05-01
- Primary Topic
- Particle physics theoretical and experimental studies
- Type
- article
- Field-Weighted Citation Impact
- 0.00