We present an observation of photon-photon production of tau 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 √s(NN) = 5.02 TeV. The gamma gamma -> tau^(+)tau^(-) process is observed for tau^(+)tau^(-) events with a muon and three charged hadrons in the final state. The measured fiducial cross section is sigma(gamma gamma ->tau^(+)tau^(-)) = 4.8 +/- 0.6(stat) +/- 0.5(syst) µb, where the second (third) term corresponds to the statistical (systematic) uncertainty in sigma(gamma gamma ->tau^(+)tau^(-)) in agreement with leading-order QED predictions. Using sigma(gamma gamma ->tau^(+)tau^(-)), we estimate a model-dependent value of the anomalous magnetic moment of the tau lepton of at alpha(tau) = 0.001(-0.089)(+0.055).
Observation of tau Lepton Pair Production in Ultraperipheral Pb-Pb Collisions at √sNN = 5.02 TeV
Cappati, A.;Meridiani, P.;Amapane, N.;Argiro, S.;Bellan, R.;Bellora, A.;Costa, M.;Covarelli, R.;Grippo, M.;Kiani, B.;Mecca, A.;Migliore, E.;Monteil, E.;Obertino, M. M.;Pacher, L.;Shchelina, K.;Siviero, F.;Sola, V.;Solano, A.;Soldi, D.;Tornago, M.;Vagnerini, A.;Rumerio, P.;Ravera, F.;Salvatico, R.;
2023-01-01
Abstract
We present an observation of photon-photon production of tau 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 √s(NN) = 5.02 TeV. The gamma gamma -> tau^(+)tau^(-) process is observed for tau^(+)tau^(-) events with a muon and three charged hadrons in the final state. The measured fiducial cross section is sigma(gamma gamma ->tau^(+)tau^(-)) = 4.8 +/- 0.6(stat) +/- 0.5(syst) µb, where the second (third) term corresponds to the statistical (systematic) uncertainty in sigma(gamma gamma ->tau^(+)tau^(-)) in agreement with leading-order QED predictions. Using sigma(gamma gamma ->tau^(+)tau^(-)), we estimate a model-dependent value of the anomalous magnetic moment of the tau lepton of at alpha(tau) = 0.001(-0.089)(+0.055).File | Dimensione | Formato | |
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PhysRevLett.131.151803.pdf
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