The European Physical Journal C > 2019 > 79 > 5 > 1-36
Measurement of the $${\mathrm {t}\overline{\mathrm {t}}}$$ tt¯ production cross section, the top quark mass, and the strong coupling constant using dilepton events in pp collisions at $$\sqrt{s}=13\,\text {Te}\text {V} $$ s=13Te
Source
Abstract
A measurement of the top quark–antiquark pair production cross section $$\sigma _{\mathrm {t}\overline{\mathrm {t}}} $$ σtt¯ in proton–proton collisions at a centre-of-mass energy of 13$$\,\text {Te}\text {V}$$ Te is presented. The data correspond to an integrated luminosity of $$35.9{\,\text {fb}^{-1}} $$ 35.9fb-1 , recorded by the CMS experiment at the CERN LHC in 2016. Dilepton events ($$\mathrm {e}$$ e $$^{\pm }$$ ± $$\mathrm {\mu }$$ μ $$^{{\mp }}$$ ∓ , $$\mathrm {\mu ^+}\mathrm {\mu ^-}$$ μ+μ- , $$\mathrm {e}^+\mathrm {e}^-$$ e+e- ) are selected and the cross section is measured from a likelihood fit. For a top quark mass parameter in the simulation of $$ m_\mathrm {\mathrm {t}} ^{\mathrm {MC}} = 172.5 \,\text {Ge}\text {V} $$ mtMC=172.5Ge the fit yields a measured cross section $$\sigma _{\mathrm {t}\overline{\mathrm {t}}} = 803 \pm 2 \,\text {(stat)} \pm 25 \,\text {(syst)} \pm 20 \,\text {(lumi)} \,\text {pb} $$ 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 $$m_\mathrm {\mathrm {t}} ^{\mathrm {MC}} = 172.33 \pm 0.14 \,\text {(stat)} \,^{+0.66}_{-0.72} \,\text {(syst)} \,\text {Ge}\text {V} $$ mtMC=172.33±0.14(stat)-0.72+0.66(syst)Ge 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.
Identifiers
journal ISSN : | 1434-6044 |
journal e-ISSN : | 1434-6052 |
DOI | 10.1140/epjc/s10052-019-6863-8 |