Korn, Andreas;
ATLAS Collaboration;
(2023)
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
, 131
, Article 151802. 10.1103/PhysRevLett.131.151802.
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Abstract
This Letter reports the observation of τ -lepton-pair production in ultraperipheral lead-lead collisions Pb + Pb → Pb ( γ γ → τ τ ) Pb and constraints on the τ -lepton anomalous magnetic moment a τ . The dataset corresponds to an integrated luminosity of 1.44 nb − 1 of LHC Pb + Pb collisions at √ s NN = 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 γ γ → τ τ process is observed in Pb + Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ τ τ = 1.0 3 + 0.06 − 0.05 assuming the standard model value for a τ . To measure a τ , a template fit to the muon transverse-momentum distribution from τ -lepton candidates is performed, using a dimuon ( γ γ → μ μ ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a τ is − 0.057 < a τ < 0.024 .
| Type: | Article |
|---|---|
| Title: | Observation of the γγ → ττ Process in Pb + Pb Collisions and Constraints on the τ-Lepton Anomalous Magnetic Moment with the ATLAS Detector |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1103/PhysRevLett.131.151802 |
| Publisher version: | https://doi.org/10.1103/PhysRevLett.131.151802 |
| Language: | English |
| Additional information: | Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3 . |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10179704 |
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