<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi mathvariant="normal">Λ</mml:mi><mml:mi>c</mml:mi></mml:msub></mml:math> semileptonic decays
Sheng‐Qi Zhang, Cong‐Feng Qiao
Abstract
Motivated by the recent experimental progress in the ${\mathrm{\ensuremath{\Lambda}}}_{c}$ decay that contains a neutron in the final state, we analyze the semileptonic decay ${\mathrm{\ensuremath{\Lambda}}}_{c}\ensuremath{\rightarrow}n\ensuremath{\ell}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ in the framework of QCD sum rules. The transition form factors are analytically computed using three-point correlation functions and the Cutkosky cutting rules, which can be extrapolated into the physical region by employing the $z$-series parametrization. The branching fractions of ${\mathrm{\ensuremath{\Lambda}}}_{c}\ensuremath{\rightarrow}n{e}^{+}{\ensuremath{\nu}}_{e}$ and ${\mathrm{\ensuremath{\Lambda}}}_{c}\ensuremath{\rightarrow}n{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ are estimated to be $(0.281\ifmmode\pm\else\textpm\fi{}0.056)%$ and $(0.275\ifmmode\pm\else\textpm\fi{}0.055)%$, respectively. Furthermore, we calculate as well the relevant decay asymmetry observables sensitive to new physics beyond the standard model. The numerical results of semileptonic decays ${\mathrm{\ensuremath{\Lambda}}}_{c}\ensuremath{\rightarrow}\mathrm{\ensuremath{\Lambda}}\ensuremath{\ell}{\ensuremath{\nu}}_{\ensuremath{\ell}}$ are also given and confronted to the latest experimental data.