Search for the decay of the Higgs boson to a Z boson and a light pseudoscalar particle decaying to two photons



Aad, G, Abbott, B, Abeling, K, Abicht, NJ, Abidi, SH, Aboulhorma, A, Abramowicz, H, Abreu, H, Abulaiti, Y, Hoffman, AC Abusleme
et al (show 2924 more authors) (2024) Search for the decay of the Higgs boson to a Z boson and a light pseudoscalar particle decaying to two photons PHYSICS LETTERS B, 850. p. 138536. ISSN 0370-2693, 1873-2445

Access the full-text of this item by clicking on the Open Access link.

Abstract

A search for the decay of the Higgs boson to a Z boson and a light, pseudoscalar particle, a, decaying respectively to two leptons and to two photons is reported. The search uses the full LHC Run 2 proton–proton collision data at s=13 TeV, corresponding to 139 fb−1 collected by the ATLAS detector. This is one of the first searches for this specific decay mode of the Higgs boson, and it probes unexplored parameter space in models with axion-like particles (ALPs) and extended scalar sectors. The mass of the a particle is assumed to be in the range 0.1–33 GeV. The data are analysed in two categories: a merged category where the photons from the a decay are reconstructed in the ATLAS calorimeter as a single cluster, and a resolved category in which two separate photons are detected. The main background processes are from Standard Model Z boson production in association with photons or jets. The data are in agreement with the background predictions, and upper limits on the branching ratio of the Higgs boson decay to Za times the branching ratio a→γγ are derived at the 95% confidence level and they range from 0.08% to 2% depending on the mass of the a particle. The results are also interpreted in the context of ALP models.

Item Type: Article
Uncontrolled Keywords: 5106 Nuclear and Plasma Physics, 5107 Particle and High Energy Physics, 51 Physical Sciences
Divisions: Faculty of Health & Life Sciences
Faculty of Science & Engineering > School of Physical Sciences
Faculty of Health & Life Sciences > Inst. Systems, Molec & Integrative Biology > Inst. Systems, Molec & Integrative Biology
Depositing User: Symplectic Admin
Date Deposited: 22 Mar 2024 08:54
Last Modified: 22 May 2026 18:56
DOI: 10.1016/j.physletb.2024.138536
Open Access URL: https://www.sciencedirect.com/science/article/pii/...
Related Websites:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3179737
Disclaimer: The University of Liverpool is not responsible for content contained on other websites from links within repository metadata. Please contact us if you notice anything that appears incorrect or inappropriate.