ausblenden:
Schlagwörter:
High Energy Physics - Experiment, hep-ex
MPINP:
LHCb - Abteilung Hofmann
Zusammenfassung:
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
$B^+\to J/\psi K^+$, $B^0\to J/\psi K^*(892)^0$, $B^0\to J/\psi K^0_{\rm S}$,
$\Lambda_b^0\to J/\psi \Lambda$ and $B^0_s\to J/\psi \phi$ 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, $\tau_{B^0\to J/\psi K^*(892)^0}$ = $1.524 \pm$
0.006 $\pm$ 0.004 ps, $\tau_{B^0\to J/\psi K^0_{\rm S}}$ = $1.499 \pm$ 0.013
$\pm$ 0.005 ps, $\tau_{\Lambda_b^0\to J/\psi \Lambda}$ = $1.415 \pm$ 0.027
$\pm$ 0.006 ps and $\tau_{B^0_s\to J/\psi \phi}$ = $1.480 \pm$ 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, $\Delta\Gamma_d$, 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.
