Searches for exclusive Higgs and Z boson decays into a vector quarkonium state and a photon using 139 fb - 1 of ATLAS √s=13 TeV proton–proton collision data

Summary, in English

Searches for the exclusive decays of Higgs and Z bosons into a vector quarkonium state and a photon are performed in the μ+μ-γ final state with a proton–proton collision data sample corresponding to an integrated luminosity of 139 fb - 1 collected at s=13 TeV with the ATLAS detector at the CERN Large Hadron Collider. The observed data are compatible with the expected backgrounds. The 95% confidence-level upper limits on the branching fractions of the Higgs boson decays into J/ψγ , ψ(2S)γ , and Υ(1S,2S,3S)γ are found to be 2.0 × 10 - 4 , 10.5 × 10 - 4 , and (2.5 , 4.2 , 3.4) × 10 - 4 , respectively, assuming Standard Model production of the Higgs boson. The corresponding 95% CL upper limits on the branching fractions of the Z boson decays are 1.2 × 10 - 6 , 2.4 × 10 - 6 , and (1.1 , 1.3 , 2.4) × 10 - 6 . An observed 95% CL interval of (- 133 , 175) is obtained for the κc/ κγ ratio of Higgs boson coupling modifiers, and a 95% CL interval of (- 37 , 40) is obtained for κb/ κγ . © 2023, The Author(s).

• Author: G. Aad; T.P.A. Åkesson; E.E. Corrigan; C. Doglioni; P.A. Ekman; J. Geisen; V. Hedberg; G. Jarlskog; B. Konya; E. Lytken; J.U. Mjörnmark; G.A. Mullier; R. Poettgen; N.D. Simpson; E. Skorda; O. Smirnova; L. Zwalinski
• Department/s: Particle and nuclear physics; eSSENCE: The e-Science Collaboration
• Publishing year: 2023
• Language: English
• Publication/Series: European Physical Journal C
• Volume: 83
• Issue: 9
• Links: http://dx.doi.org/10.1140/epjc/s10052-023-11869-1
• Document type: Journal article
• Publisher: Springer
• Topic: Subatomic Physics
• Status: Published
• ISBN/ISSN/Other: ISSN: 1434-6044