Two-body Cabibbo-suppressed Decays of Charmed Baryons into Vector Mesons and into Photons

Abstract

The heavy quark effective theory and the factorization approximation are used to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons, ${\Lambda }_C\to p{\rho }^0,p\omega$, ${\Xi }_C^{+,0}\to {\Sigma }^{+,0}\varphi ,{\Sigma }^{+,0}{\rho }^0,{\Sigma }^{+,0}\omega$ and ${\Xi }_C^0\to \Lambda \varphi ,\Lambda \rho ,\Lambda \omega$. The input from two recent experimental results on ${\Lambda }_C$ decays allows the estimation of the branching ratios for these modes, which turn out to be between $10^{-4}$ and $10^{-3}$. The long distance contribution of these transitions via vector meson dominance to the radiative weak processes ${\Lambda }_C\to p\gamma$, ${\Xi }_C\to \Sigma \gamma$ and ${\Xi }_C^0\to \Lambda \gamma$ leads to quite small branching ratios, $10^{-6}-10^{-9}$; the larger value holds if a sum rule between the coupling constants of the vector mesons is broken.

Comments: 11 pages, latex, no figures