${\Lambda }_c$ semileptonic decays

Abstract

Motivated by the recent experimental progress in the ${\Lambda }_c$ decay that contains a neutron in the final state, we analyze the semileptonic decay ${\Lambda }_c\to n\ell {\nu }_{\ell }$ 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 ${\Lambda }_c\to n{e}^{+}{\nu }_e$ and ${\Lambda }_c\to n{\mu }^{+}{\nu }_{\mu }$ are estimated to be $(0.281\pm 0.056)\%$ and $(0.275\pm 0.055)\%$, 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 ${\Lambda }_c\to \Lambda \ell {\nu }_{\ell }$ are also given and confronted to the latest experimental data.

Comments: 18 pages, 5 figures, 3 tables