$Λ_c$ Semileptonic Decays in a Quark Model

Abstract

Hadronic form factors for semileptonic decay of the $Λ_c$ are calculated in a nonrelativistic quark model. The full quark model wave functions are employed to numerically calculate the form factors to all relevant orders in ($1/m_c$, $1/m_s$). The form factors obtained satisfy relationships expected from the heavy quark effective theory (HQET). The differential decay rates and branching fractions are calculated for transitions to the ground state and a number of excited states of $Λ$. The branching fraction of the semileptonic decay width to the total width of $Λ_c$ has been calculated and compared with other theoretical estimates and experimental results. The branching fractions for $Λ_c\toΛ^{*} l^{+}ν_l\toΣπl^{+}ν_l$ and $Λ_c\toΛ^{*} l^{+}ν_l\to N\bar{K} l^{+}ν_l$ are also calculated. Apart from decays to the ground state $Λ$(1115), it is found that decays through the $Λ(1405)$ provide a significant portion of the branching fraction $Λ_c\to X_s lν_l$. A new estimate for $f=B(Λ_c^{+}\toΛl^{+}ν_l)/B(Λ_c^{+}\to X_s l^{+}ν_l)$ is obtained.