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

Aad, G. ; Åkesson, T.P.A. LU orcid ; Doglioni, C. LU ; Ekman, P.A. LU ; Hedberg, V. LU ; Herde, H. LU orcid ; Konya, B. LU ; Lytken, E. LU orcid ; Poettgen, R. LU orcid and Simpson, N.D. LU , et al. (2024) In Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 850.
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... (More)
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. © 2024 The Author(s) (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
volume
850
article number
138536
publisher
Elsevier
external identifiers
  • scopus:85186584048
ISSN
0370-2693
DOI
10.1016/j.physletb.2024.138536
language
English
LU publication?
yes
id
0f387fc9-821d-45d0-91bc-5424530637da
date added to LUP
2024-03-27 13:30:36
date last changed
2024-03-27 13:31:06
@article{0f387fc9-821d-45d0-91bc-5424530637da,
  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. © 2024 The Author(s)}},
  author       = {{Aad, G. and Åkesson, T.P.A. and Doglioni, C. and Ekman, P.A. and Hedberg, V. and Herde, H. and Konya, B. and Lytken, E. and Poettgen, R. and Simpson, N.D. and Smirnova, O. and Zwalinski, L.}},
  issn         = {{0370-2693}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics}},
  title        = {{Search for the decay of the Higgs boson to a Z boson and a light pseudoscalar particle decaying to two photons}},
  url          = {{http://dx.doi.org/10.1016/j.physletb.2024.138536}},
  doi          = {{10.1016/j.physletb.2024.138536}},
  volume       = {{850}},
  year         = {{2024}},
}