Semileptonic decays of ${\Lambda }_c^{+}$ in light-front quark model with nonvalence contributions

Abstract

We investigate the exclusive semilpetonic decays of ${\Lambda }_c^{+}\to (\Lambda /n){\ell }^{+}{\nu }_{\ell }(\ell =e,\mu )$ within the standard model by using the light-front quark model (LFQM). The form factor behaviors are obtained from the effective treatment of nonvalence contributions in addition to the valence ones in the Drell-Yan-West frame due to the Bethe-Salpeter formalism. Based on these form factors, we find that the decay branching ratios of ${\Lambda }_c^{+}\to (\Lambda e^{+}{\nu }_e,\Lambda {\mu }^{+}{\nu }_e,n{e}^{+}{\nu }_e,n{\mu }^{+}{\nu }_e)$ are about $(3.39,3.21,0.36,0.35)\%$ with the non-valence contributions, which are consistent with the recent experimental measurements at BESIII. Furthermore, we use the experimental data to fit the $\beta$ parameters in the baryonic distribution amplitudes under the LFQM, resulting in (${\beta }_{{\Lambda }_c},{\beta }_{\Lambda },{\beta }_n)=(0.58\pm 0.08,0.52\pm 0.08,0.44\pm 0.04)$.