اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMeasurement of $B^{0}_{s}$ and $D^{-}_{s}$ meson lifetimes
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We report on a measurement of the flavor-specific $B^{0}_{s}$ lifetime and of the $D^{-}_{s}$ lifetime using proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to 3.0 fb$^{-1}$ of integrated luminosity. Approximately 407 000 $B^{0}_{s} rightarrow D^{(*)-}_{s} mu^{+} u_mu $ decays are partially reconstructed in the $K^{+}K^{-}pi^{-}mu^{+}$ final state. The $B^{0}_{s}$ and $D^{-}_{s}$ natural widths are determined using, as a reference, kinematically similar $B^{0} rightarrow D^{(*)-}mu^{+} u_mu$ decays reconstructed in the same final state. The resulting differences between widths of $B^{0}_{s}$ and $B^{0}$ mesons and of $D^{-}_{s}$ and $D^{-}$ mesons are $Delta_Gamma(B) =-0.0115 pm 0.0053 (stat) pm 0.0041 (syst)$ ps$^{-1}$ and $Delta_Gamma(D) = 1.0131 pm 0.0117 (stat) pm 0.0065 (syst)$ ps$^{-1}$, respectively. Combined with the known $B^{0}$ and $D^{-}$ lifetimes, these yield the flavor-specific $B^{0}_{s}$ lifetime, $tau^{rm fs}_{B^{0}_{s}} = 1.547 pm 0.013 (stat) pm 0.010 (syst) pm 0.004 (tau_{B})$ ps and the $D^{-}_{s}$ lifetime, $tau_{D^{-}_{s}} = 0.5064 pm 0.0030 (stat) pm 0.0017 (syst) pm 0.0017 (tau_{D})$ ps The last uncertainties originate from the limited knowledge of the $B^0$ and $D^{-}$ lifetimes. The results improve upon current determinations.
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The decay mode $B^{0}_{s} to D^{mp}_{s} K^{pm} $ allows for one of the theoretically cleanest measurements of the CKM angle $gamma$ through the study of time-dependent $ensuremath{CP}xspace$ violation. This paper reports a measurement of its branchin
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Measurements of $b$-hadron lifetimes are reported using $pp$ collision data, corresponding to an integrated luminosity of 1.0fb$^{-1}$, collected by the LHCb detector at a centre-of-mass energy of $7$Tev. Using the exclusive decays $B^+to J/psi K^+$,
$B^0to J/psi K^*(892)^0$, $B^0to J/psi K^0_{rm S}$, $Lambda_b^0to J/psi Lambda$ and $B^0_sto J/psi phi$ the average decay times in these modes are measured to be $tau_{B^+to J/psi K^+}$ = $1.637 pm$ 0.004 $pm$ 0.003 ps, $tau_{B^0to J/psi K^*(892)^0}$ = $1.524 pm$ 0.006 $pm$ 0.004 ps, $tau_{B^0to J/psi K^0_{rm S}}$ = $1.499 pm$ 0.013 $pm$ 0.005 ps, $tau_{Lambda_b^0to J/psi Lambda}$ = $1.415 pm$ 0.027 $pm$ 0.006 ps and $tau_{B^0_sto J/psi phi}$ = $1.480 pm$ 0.011 $pm$ 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, $DeltaGamma_d$, to the average width, $Gamma_d$, in the $B^0$ system, $Delta Gamma_d/Gamma_d = -0.044 pm 0.025 pm 0.011$, are reported. All quantities are found to be consistent with Standard Model expectations.
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