Observation of τ Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at √sNN=5.02  TeV

Physical Review Letters 2023
Kārlis Dreimanis, Antra Gaile, Andris Potrebko, Toms Torims, Viesturs Veckalns, CMS Collaboration

We present an observation of photon-photon production of τ lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404  μb−1 collected by the CMS experiment at a center-of-mass energy per nucleon pair of √sNN=5.02  TeV. The γγ→τ+τ− process is observed for τ+τ− events with a muon and three charged hadrons in the final state. The measured fiducial cross section is σ(γγ→τ+τ−)=4.8±0.6(stat)±0.5(syst)  μb, where the second (third) term corresponds to the statistical (systematic) uncertainty in σ(γγ→τ+τ−) in agreement with leading-order QED predictions. Using σ(γγ→τ+τ−), we estimate a model-dependent value of the anomalous magnetic moment of the τ lepton of aτ=0.001+0.055−0.089.

DOI
10.1103/PhysRevLett.131.151803
Hyperlink
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.131.151803

The CMS Collaboration, A.Tumasyan, K.Dreimanis, A.Gaile, A.Potrebko, T.Torims, V.Veckalns ... [et al.]. Observation of τ Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at √sNN=5.02  TeV. Physical Review Letters, 2023, Vol. 131, No. 15, Article number 151803. ISSN 0031-9007. e-ISSN 1079-7114. Available from: doi:10.1103/PhysRevLett.131.151803

Publication language
English (en)