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

Abstract

We first calculate the binding energy, the pionic and electromagnetic couping constants of the lowest lying p-wave heavy baryon doublet ${\Lambda }_{c1}$, ${\Lambda }_{c1}^{\ast }$ 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 $\Gamma ({\Lambda }_{c1}\to {\Sigma }_c\pi ,{\Sigma }_c\gamma ,{\Sigma }_c^{\ast }\gamma )=2.7,0.011,0.001$ MeV and $\Gamma ({\Lambda }_{c1}^{\ast }\to {\Sigma }_c\pi ,{\Sigma }_c\gamma ,{\Sigma }_c^{\ast }\gamma ,{\Lambda }_{c1}\gamma )=33,5,6,0.014$ keV respectively. We find ${\Lambda }_{c1},{\Lambda }_{c1}^{\ast }\to {\Lambda }_c\gamma$ is strictly forbidden in the leading order of the heavy quark expansion. At the order of $\mathcal{O}(1/m_c)$ their widths are $36,48$ keV respectively.