Measurement of the Absolute Branching Fraction of the Inclusive Decay Λc+→Λ+X

Le résumé fourni par la source

Based on an ${e}^{+}{e}^{\ensuremath{-}}$ collision data sample corresponding to an integrated luminosity of $567\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ taken at the center-of-mass energy of $\sqrt{s}=4.6\text{ }\text{ }\mathrm{GeV}$ with the BESIII detector, we measure the absolute branching fraction of the inclusive decay ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}+X$ to be $\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}+X)=(38.{2}_{\ensuremath{-}2.2}^{+2.8}\ifmmode\pm\else\textpm\fi{}0.9)%$ using the double-tag method, where $X$ refers to any possible final state particles. In addition, we search for direct $CP$ violation in the charge asymmetry of this inclusive decay for the first time, and obtain ${\mathcal{A}}_{CP}\ensuremath{\equiv}\phantom{\rule{0ex}{0ex}}[\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}+X)\ensuremath{-}\mathcal{B}({\overline{\mathrm{\ensuremath{\Lambda}}}}_{c}^{\ensuremath{-}}\ensuremath{\rightarrow}\overline{\mathrm{\ensuremath{\Lambda}}}+X)]/[\mathcal{B}({\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}+X)+\mathcal{B}({\overline{\mathrm{\ensuremath{\Lambda}}}}_{c}^{\ensuremath{-}}\ensuremath{\rightarrow}\overline{\mathrm{\ensuremath{\Lambda}}}+X)]=(2.{1}_{\ensuremath{-}6.6}^{+7.0}\ifmmode\pm\else\textpm\fi{}1.6)%$, a statistically limited result with no evidence of $CP$ violation.

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