6 research outputs found

    Measurement of b hadron lifetimes in pp collisions at root s=8TeV

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    Correction: DOI:10.1140/epjc/s10052-018-6014-7Measurements are presented of the lifetimes of the B-0, B-s(0), Lambda(0)(b), and B-c(+) hadrons using the decay channels B-0 -> J/psi K*(892)(0), B-0 -> J/psi K-S(0), B-s(0) -> J/psi pi(+)pi(-), B-s(0) -> J/psi phi(1020), Lambda(0)(b) -> J/psi Lambda(0), and B-c(+) -> J/psi pi(+). The data sample, corresponding to an integrated luminosity of 19.7 fb(-1), was collected by the CMS detector at the LHC in proton-proton collisions at root s = 8TeV. The B-0 life-time is measured to be 453.0 +/- 1.6 (stat) +/- 1.8 (syst) mu m in J/psi K*(892)(0) and 457.8 +/- 2.7 (stat) +/- 2.8 (syst) mu m in J/psi K-S(0), which results in a combined measurement of c tau(0) = 454.1 +/- 1.4 (stat) +/- 1.7 (syst) mu m. The effective lifetime of the B-s(0) meson is measured in two decay modes, with contributions from different amounts of the heavy and light eigenstates. This results in two different measured lifetimes: c tau(0)(Bs) -> J/psi pi(+)pi(-) = 502.7 +/- 10.2 (stat) +/- 3.4 (syst) mu m and c tau(0)(Bs) -> J/psi phi(1020) = 443.9 +/- 2.0 (stat) +/- 1.5 (syst) mu m. The Lambda(0)(b) lifetime is found to be 442.9 +/- 8.2 (stat) +/- 2.8 (syst) mu m. The precision from each of these channels is as good as or better than previous measurements. The B-c(+) lifetime, measured with respect to the B+ to reduce the systematic uncertainty, is 162.3 +/- 7.8 (stat) +/- 4.2 (syst) +/- 0.1 (tau(B+)) mu m. All results are in agreement with current world-average values.Peer reviewe

    Measurement of b hadron lifetimes in pp collisions at √ s = 8TeV

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    Measurements are presented of the lifetimes of the B0 , Bs0 , Λb0 , and Bc+ hadrons using the decay channels B0→J/ψK∗(892)0 , B0→J/ψKS0 , Bs0→J/ψπ+π- , Bs0→J/ψϕ(1020) , Λb0→J/ψΛ0 , and Bc+→J/ψπ+ . The data sample, corresponding to an integrated luminosity of 19.7 fb-1 , was collected by the CMS detector at the LHC in proton–proton collisions at s=8TeV . The B0 lifetime is measured to be 453.0±1.6(stat)±1.8(syst)μm in J/ψK∗(892)0 and 457.8±2.7(stat)±2.8(syst)μm in J/ψKS0 , which results in a combined measurement of cτB0=454.1±1.4(stat)±1.7(syst)μm . The effective lifetime of the Bs0 meson is measured in two decay modes, with contributions from different amounts of the heavy and light eigenstates. This results in two different measured lifetimes: cτBs0→J/ψπ+π-=502.7±10.2(stat)±3.4(syst)μm and cτBs0→J/ψϕ(1020)=443.9±2.0(stat)±1.5(syst)μm . The Λb0 lifetime is found to be 442.9±8.2(stat)±2.8(syst)μm . The precision from each of these channels is as good as or better than previous measurements. The Bc+ lifetime, measured with respect to the B+ to reduce the systematic uncertainty, is 162.3±7.8(stat)±4.2(syst)±0.1(τB+)μm . All results are in agreement with current world-average values

    Measurement of b hadron lifetimes in pp collisions at <tex>\sqrt{s}$</tex>=8TeV

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    Measurement of nuclear modification factors of <tex>\Upsilon</tex>(1S)),<tex>Υ</tex>(1S)), <tex>\Upsilon</tex>(2S), and <tex>\Upsilon</tex>(3S)mesonsinPbPbcollisionsat<tex>sNN</tex>(3S) mesons in PbPb collisions at <tex>\sqrt{s_{NN}}</tex>=5.02 TeV

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    Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

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    The cross sections for gamma(1S), gamma(2S), and gamma(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at root s(NN) = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, R-AA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, R-AA(T(1S)) > R-AA(gamma(2S)) > R-AA(gamma(3S)). The suppression of gamma(1S) is larger than that seen at root s(NN) = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the R-AA of gamma(3S) integrated over p(T), rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. (C) 2019 The Author(s). Published by Elsevier B.V
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