Semileptonic $\Lambda_c \to \Lambda \ell \nu_\ell$ Decays in Light-Cone QCD Sum Rules with $\Lambda_c$ Distribution Amplitudes

Abstract

We study the semileptonic decay of its SU(3) partner, the $\Lambda_c \to \Lambda \ell^+ \nu_\ell$ ($\ell = e, \mu$) transition, within the framework of light-cone QCD sum rules (LCSR) by using the distribution amplitudes of heavy $\Lambda_c$ baryon. The numerical analysis is performed using two different sets of $\Lambda_c$ baryon light-cone distribution amplitudes. The resulting form factors are parametrized by a model-independent $z$-series expansion and used to compute the differential and total decay widths. Our predictions for the branching fractions are in good agreement with the latest BESIII measurements and with lattice-QCD results.