(\Lambda_c\) Semileptonic Decays in a Quark Model

Hadronic form factors for semileptonic decay of the \(\Lambda_c\) 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 \(\Lambda\). The branching fraction of the semileptonic decay width to the total width of \(\Lambda_c\) has been calculated and compared with other theoretical estimates and experimental results. The branching fractions for \(\Lambda_c\to\Lambda^{*} l^{+}\nu_l\to\Sigma\pi l^{+}\nu_l\) and \(\Lambda_c\to\Lambda^{*} l^{+}\nu_l\to N\bar{K} l^{+}\nu_l\) are also calculated. Apart from decays to the ground state \(\Lambda\)(1115), it is found that decays through the \(\Lambda(1405)\) provide a significant portion of the branching fraction \(\Lambda_c\to X_s l\nu_l\). A new estimate for \(f=B(\Lambda_c^{+}\to\Lambda l^{+}\nu_l)/B(\Lambda_c^{+}\to X_s l^{+}\nu_l)\) is obtained.