Strong and electromagnetic decays of p-wave heavy baryons $\Lambda_{c1}, \Lambda^*_{c1}$

Abstract

We first calculate the binding energy, the pionic and electromagnetic couping constants of the lowest lying p-wave heavy baryon doublet $\Lambda_{c1}$, $\Lambda_{c1}^*$ in the leading order of the heavy quark expansion. Then we calculate the two-body decay widths with these couplings and compare our results with other approaches. Our results are $\Gamma (\Lambda_{c1}\to \Sigma_c \pi, \Sigma_c \gamma, \Sigma^*_c \gamma) =2.7, 0.011, 0.001$ MeV and $\Gamma (\Lambda^*_{c1}\to \Sigma_c \pi, \Sigma_c \gamma, \Sigma^*_c \gamma, \Lambda_{c1} \gamma) =33, 5, 6, 0.014$ keV respectively. We find $\Lambda_{c1}, \Lambda^*_{c1}\to \Lambda_c \gamma$ is strictly forbidden in the leading order of the heavy quark expansion. At the order of ${\cal O} (1/m_c)$ their widths are $36, 48$ keV respectively.