Semileptonic $B$ and $B_s$ decays into orbitally excited charmed mesons

Abstract

The BaBar Collaboration has recently reported products of branching fractions that include $B$ meson semileptonic decays into final states with charged and neutral $D_1(2420)$ and $D_2^{\ast }(2460)$, two narrow orbitally excited charmed mesons. We evaluate these branching fractions, together with those concerning $D_0^{\ast }(2400)$ and $D_1^{\prime }(2430)$ mesons, within the framework of a constituent quark model. The calculation is performed in two steps, one of which involves a semileptonic decay and the other is mediated by a strong process. Our results are in agreement with the experimental data. We also extend the study to semileptonic decays of $B_s$ into orbitally excited charmed-strange mesons, providing predictions to the possible measurements to be carried out at LHC.

Comments: Physical Review D 84, 094029 (2011). 20 pages, 9 figures