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

ATLAS Collaboration; S. Alderweireldt; J.F. Allen; T.M. Carter; P. J.  Clark; D. Duda; S. M. Farrington; Y. Gao; J.M. Gargan; R.Y. Gonzalez Andana; C. Leonidopoulos; V. J.  Martin; L. Mijović; V.A. Parrish; E.A. Pender; T. Qiu; E.P. Takeva; N. Themistokleous; E.M. Villhauer; B.M. Wynne; Z. Xu; E. Zaid

doi:10.1016/j.physletb.2024.138536

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

ATLAS Collaboration, S. Alderweireldt, J.F. Allen, T.M. Carter, P. J. Clark, D. Duda, S. M. Farrington, Y. Gao, J.M. Gargan, R.Y. Gonzalez Andana, C. Leonidopoulos, V. J. Martin, L. Mijović, V.A. Parrish, E.A. Pender, T. Qiu, E.P. Takeva, N. Themistokleous, E.M. Villhauer, B.M. WynneZ. Xu, E. Zaid

School of Physics and Astronomy

Research output: Contribution to journal › Letter › peer-review

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.

Original language	English
Article number	138536
Pages (from-to)	1-24
Number of pages	24
Journal	Physics Letters B
Volume	850
Early online date	21 Feb 2024
DOIs	https://doi.org/10.1016/j.physletb.2024.138536
Publication status	Published - 1 Mar 2024

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3 Finished
3 Active

Experimental Particle Physics at the University of Edinburgh
Leonidopoulos, C. (Principal Investigator)
Science and Technology Facilities Council
1/04/23 → 31/03/26
Project: Research
Upgrade of the ATLAS detector at the LHC (2023-26)
Clark, P. (Principal Investigator)
Science and Technology Facilities Council
1/04/23 → 31/03/26
Project: Research
Experimental Particle Physics at the University of Edinburgh
Leonidopoulos, C. (Principal Investigator)
Science and Technology Facilities Council
1/10/22 → 31/03/26
Project: Research

Cite this

ATLAS Collaboration, Alderweireldt, S., Allen, J. F., Carter, T. M., Clark, P. J., Duda, D., Farrington, S. M., Gao, Y., Gargan, J. M., Gonzalez Andana, R. Y., Leonidopoulos, C., Martin, V. J., Mijović, L., Parrish, V. A., Pender, E. A., Qiu, T., Takeva, E. P., Themistokleous, N., Villhauer, E. M., ... Zaid, E. (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, 1-24. Article 138536. https://doi.org/10.1016/j.physletb.2024.138536

@article{201a780771814ac1b8a82dc237c07f1f,

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

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 reconstructedin 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.",

author = "{ATLAS Collaboration} and S. Alderweireldt and J.F. Allen and T.M. Carter and Clark, {P. J.} and D. Duda and Farrington, {S. M.} and Y. Gao and J.M. Gargan and {Gonzalez Andana}, R.Y. and C. Leonidopoulos and Martin, {V. J.} and L. Mijovi{\'c} and V.A. Parrish and E.A. Pender and T. Qiu and E.P. Takeva and N. Themistokleous and E.M. Villhauer and B.M. Wynne and Z. Xu and E. Zaid",

year = "2024",

month = mar,

day = "1",

doi = "10.1016/j.physletb.2024.138536",

language = "English",

volume = "850",

pages = "1--24",

journal = "Physics Letters B",

issn = "0370-2693",

publisher = "Elsevier",

}

ATLAS Collaboration, Alderweireldt, S, Allen, JF, Carter, TM, Clark, PJ , Duda, D , Farrington, SM , Gao, Y, Gargan, JM, Gonzalez Andana, RY, Leonidopoulos, C , Martin, VJ , Mijović, L, Parrish, VA, Pender, EA, Qiu, T, Takeva, EP, Themistokleous, N, Villhauer, EM, Wynne, BM , Xu, Z & Zaid, E 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, vol. 850, 138536, pp. 1-24. https://doi.org/10.1016/j.physletb.2024.138536

TY - JOUR

T1 - Search for the decay of the Higgs boson to a 𝑍 boson and a light pseudoscalar particle decaying to two photons

AU - ATLAS Collaboration

AU - Alderweireldt, S.

AU - Allen, J.F.

AU - Carter, T.M.

AU - Clark, P. J.

AU - Duda, D.

AU - Farrington, S. M.

AU - Gao, Y.

AU - Gargan, J.M.

AU - Gonzalez Andana, R.Y.

AU - Leonidopoulos, C.

AU - Martin, V. J.

AU - Mijović, L.

AU - Parrish, V.A.

AU - Pender, E.A.

AU - Qiu, T.

AU - Takeva, E.P.

AU - Themistokleous, N.

AU - Villhauer, E.M.

AU - Wynne, B.M.

AU - Xu, Z.

AU - Zaid, E.

PY - 2024/3/1

Y1 - 2024/3/1

N2 - 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 reconstructedin 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.

AB - 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 reconstructedin 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.

U2 - 10.1016/j.physletb.2024.138536

DO - 10.1016/j.physletb.2024.138536

M3 - Letter

SN - 0370-2693

VL - 850

SP - 1

EP - 24

JO - Physics Letters B

JF - Physics Letters B

M1 - 138536

ER -

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

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Experimental Particle Physics at the University of Edinburgh

Upgrade of the ATLAS detector at the LHC (2023-26)

Experimental Particle Physics at the University of Edinburgh

Cite this