B decays into radially excited charmed mesons

Abstract

It has been recently argued that some longstanding problems in semileptonic B decays can be solved provided the branching ratio for the $B\to D^{\prime (\ast )}$ semileptonic decays are large enough. We have studied these decays in a constituent quark model which has been successful in describing semileptonic and non-leptonic B decays into orbitally excited charmed mesons. Our results do not confirm the hypothesis of large branching ratios for the $B\to D^{\prime (\ast )}$ semileptonic decays. In addition, we calculate the non-leptonic $B\to D^{\prime }\pi$ decays which can provide an independent test of the form factors involved in the $B\to D^{\prime (\ast )}$ reactions.

Comments: 6 pages, 3 figures. An estimation of the theoretical uncertainties and minor changes have been done