Radiative Decays of Excited ${\Lambda }_Q$ Baryons in the Bound State Picture

Abstract

It is shown that, in the bound state picture, the ${\Lambda }_c(2593)\to {\Lambda }_c\gamma$ and ${\Lambda }_c(2625)\to {\Lambda }_c\gamma$ decays are severely suppressed. On the other hand, for their bottom counterparts, which are predicted to have masses 5900 and 5926 MeV respectively, may have significant radiative branching ratio. In particular, the ${\Lambda }_b(5926)\to {\Lambda }_b\gamma$ mode may even dominate over the strong decay mode. The isospin allowed ${\Lambda }_Q^{\ast \ast }\to {\Sigma }_Q\gamma$ mode is expected to be small.

Comments: 8 pages in REVTeX, no figures