Nonleptonic ${\Lambda }_b$ decays to $D_s(2317)$, $D_s(2460)$ and other final states in Factorization

Abstract

We consider nonleptonic Cabibbo--allowed ${\Lambda }_b$ decays in the factorization approximation. We calculate nonleptonic decays of the type ${\Lambda }_b\to {\Lambda }_{c}P$ and ${\Lambda }_b\to {\Lambda }_{c}V$ relative to ${\bar{B}}_d\to D^{+}P$ and ${\bar{B}}_d\to D^{+}V$ where we include among the pseudoscalar states(P) and the vector states(V) the newly discovered $D_s$ resonances, $D_s(2317)$ and $D_s(2460)$. In the ratio of ${\Lambda }_b$ decays to $D_s(2317)$ and $D_s(2460)$ relative to the ${\bar{B}}_d$ decays to these states, the poorly known decay constants of $D_s(2317)$ and $D_s(2460)$ cancel leading to predictions that can shed light on the nature of these new states. In general, we predict the ${\Lambda }_b$ decays to be larger than the corresponding ${\bar{B}}_d$ decays and in particular we find the branching ratio for ${\Lambda }_b\to {\Lambda }_c{D}_s(2460)$ can be between four to five times the branching ratio for ${\bar{B}}_d\to D^{+}{D}_s(2460)$. This enhancement of ${\Lambda }_b$ branching ratios follows primarily from the fact that more partial waves contribute in ${\Lambda }_b$ decays than in ${\bar{B}}_d$ decays. Our predictions are largely independent of model calculations of hadronic inputs like form factors and decay constants.

Comments: 16 pages LaTeX