Measurement of Bs0 and Ds− Meson Lifetimes

Le résumé fourni par la source

We report on a measurement of the flavor-specific ${B}_{s}^{0}$ lifetime and of the ${D}_{s}^{\ensuremath{-}}$ lifetime using proton-proton collisions at center-of-mass energies of 7 and 8 TeV, collected by the LHCb experiment and corresponding to $3.0\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity. Approximately 407 000 ${B}_{s}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ decays are partially reconstructed in the ${K}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}$ final state. The ${B}_{s}^{0}$ and ${D}_{s}^{\ensuremath{-}}$ natural widths are determined using, as a reference, kinematically similar ${B}^{0}\ensuremath{\rightarrow}{D}^{(*)\ensuremath{-}}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ decays reconstructed in the same final state. The resulting differences between widths of ${B}_{s}^{0}$ and ${B}^{0}$ mesons and of ${D}_{s}^{\ensuremath{-}}$ and ${D}^{\ensuremath{-}}$ mesons are ${\mathrm{\ensuremath{\Delta}}}_{\mathrm{\ensuremath{\Gamma}}}(B)=\ensuremath{-}0.0115\ifmmode\pm\else\textpm\fi{}0.0053(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.0041(\mathrm{syst})\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$ and ${\mathrm{\ensuremath{\Delta}}}_{\mathrm{\ensuremath{\Gamma}}}(D)=1.0131\ifmmode\pm\else\textpm\fi{}0.0117(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.0065(\mathrm{syst})\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$, respectively. Combined with the known ${B}^{0}$ and ${D}^{\ensuremath{-}}$ lifetimes, these yield the flavor-specific ${B}_{s}^{0}$ lifetime, ${\ensuremath{\tau}}_{{B}_{s}^{0}}^{\mathrm{fs}}=1.547\ifmmode\pm\else\textpm\fi{}0.013(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.010(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.004({\ensuremath{\tau}}_{B})\text{ }\text{ }\mathrm{ps}$ and the ${D}_{s}^{\ensuremath{-}}$ lifetime, ${\ensuremath{\tau}}_{{D}_{s}^{\ensuremath{-}}}=0.5064\ifmmode\pm\else\textpm\fi{}0.0030(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.0017(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.0017({\ensuremath{\tau}}_{D})\text{ }\text{ }\mathrm{ps}$. The last uncertainties originate from the limited knowledge of the ${B}^{0}$ and ${D}^{\ensuremath{-}}$ lifetimes. The results improve upon current determinations.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.