Observation of the γγ→ττ process in Pb+Pb collisions and constraints on the τ-lepton anomalous magnetic moment with the ATLAS detector

0579028 - FZÚ 2024 RIV US eng J - Journal Article
Aad, G. - Abbott, B. - Abbott, D.C. - Chudoba, Jiří - Hejbal, Jiří - Jačka, Petr - Kepka, Oldřich - Kroll, Jiří - Kupčo, Alexander - Latoňová, Věra - Lokajíček, Miloš - Lysák, Roman - Marčišovský, Michal - Mikeštíková, Marcela - Němeček, Stanislav - Šícho, Petr - Staroba, Pavel - Svatoš, Michal - Taševský, Marek … Total 2914 authors
Observation of the γγ→ττ process in Pb+Pb collisions and constraints on the τ-lepton anomalous magnetic moment with the ATLAS detector.
Physical Review Letters. Roč. 131, č. 15 (2023), č. článku 151802. ISSN 0031-9007. E-ISSN 1079-7114
Research Infrastructure: CERN-CZ III - 90240
Institutional support: RVO:68378271
Keywords : tau: magnetic moment * anomaly * ATLAS * tau: pair production
OECD category: Particles and field physics
Impact factor: 8.6, year: 2022
Method of publishing: Open access

This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+Pb→Pb(γγ→ττ)Pb and constraints on the τ-lepton anomalous magnetic moment aτ. The dataset corresponds to an integrated luminosity of 1.44  nb-1 of LHC Pb+Pb collisions at sNN=5.02  TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track(s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γγ→ττ process is observed in Pb+Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μττ=1.03-0.05+0.06 assuming the standard model value for aτ. To measure aτ, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γγ→μμ) control sample to constrain systematic uncertainties.
Permanent Link: https://hdl.handle.net/11104/0347907