A measurement of the top quark–antiquark pair production cross section σ (tt ¯ ) in proton–proton collisions at a centre-of-mass energy of 13Te is presented. The data correspond to an integrated luminosity of 35.9fb-1, recorded by the CMS experiment at the CERN LHC in 2016. Dilepton events (e± μ∓ , μ+ μ- , e+ e- ) are selected and the cross section is measured from a likelihood fit. For a top quark mass parameter in the simulation of mtMC=172.5Ge the fit yields a measured cross section σtt¯=803±2(stat)±25(syst)±20(lumi)pb, in agreement with the expectation from the standard model calculation at next-to-next-to-leading order. A simultaneous fit of the cross section and the top quark mass parameter in the powheg simulation is performed. The measured value of mt_MC = 172.33±0.14(stat)-0.72+0.66(syst)GeV is in good agreement with previous measurements. The resulting cross section is used, together with the theoretical prediction, to determine the top quark mass and to extract a value of the strong coupling constant with different sets of parton distribution functions.
Measurement of the tt¯ production cross section, the top quark mass, and the strong coupling constant using dilepton events in pp collisions at √s=13TeV
Meridiani P.;Amapane N.;Argiro S.;Bellan R.;Cappati A.;Costa M.;Covarelli R.;Kiani B.;Migliore E.;Monaco V.;Monteil E.;Obertino M. M.;Pacher L.;Angioni G. L. P.;Romero A.;Sacchi R.;Salvatico R.;Shchelina K.;Sola V.;Solano A.;Soldi D.;Rumerio P.;Ravera F.;
2019-01-01
Abstract
A measurement of the top quark–antiquark pair production cross section σ (tt ¯ ) in proton–proton collisions at a centre-of-mass energy of 13Te is presented. The data correspond to an integrated luminosity of 35.9fb-1, recorded by the CMS experiment at the CERN LHC in 2016. Dilepton events (e± μ∓ , μ+ μ- , e+ e- ) are selected and the cross section is measured from a likelihood fit. For a top quark mass parameter in the simulation of mtMC=172.5Ge the fit yields a measured cross section σtt¯=803±2(stat)±25(syst)±20(lumi)pb, in agreement with the expectation from the standard model calculation at next-to-next-to-leading order. A simultaneous fit of the cross section and the top quark mass parameter in the powheg simulation is performed. The measured value of mt_MC = 172.33±0.14(stat)-0.72+0.66(syst)GeV is in good agreement with previous measurements. The resulting cross section is used, together with the theoretical prediction, to determine the top quark mass and to extract a value of the strong coupling constant with different sets of parton distribution functions.File | Dimensione | Formato | |
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