Semileptonic Decays of $\Lambda \to p{\ell }^{-}{\bar{\nu }}_{\ell }$ in the Light-Front Dynamics

Abstract

We investigate the exclusive semileptonic decays of $\Lambda \to p{\ell }^{-}{\bar{\nu }}_{\ell }(\ell =e,\mu )$ within the Standard Model using the light-front quark model. The transition form factor behaviors of $\Lambda \to p$ 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 obtain that the branching ratios of $\Lambda \to p{e}^{-}{\bar{\nu }}_e$ and $p{\mu }^{-}{\bar{\nu }}_{\mu }$, including nonvalence contributions, are around $8.32\times 10^{-4}$ and $1.31\times 10^{-4}$, which are consistent with the latest measurements from the BESIII Collaboration, respectively. Our results indicate that nonvalence contributions can play a non-negligible role in the semileptonic baryon decays within the light-front framework.