We present an observation of photon-photon production of t lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404 mu b(-1) collected by the CMS experiment at a center-of-mass energy per nucleon pair of root 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) mu b, 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 t lepton of at a(tau) = 0.001(-0.089)(+0.055).

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

Bortignon, P.;Bragagnolo, A.;Carlin, R.;Gasparini, U.;Margoni, M.;Pazzini, J.;Ronchese, P.;Rossin, R.;Strong, G.;Tosi, M.;Zanetti, M.;Zotto, P.;
2023

Abstract

We present an observation of photon-photon production of t lepton pairs in ultraperipheral lead-lead collisions. The measurement is based on a data sample with an integrated luminosity of 404 mu b(-1) collected by the CMS experiment at a center-of-mass energy per nucleon pair of root 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) mu b, 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 t lepton of at a(tau) = 0.001(-0.089)(+0.055).
2023
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3506952
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