Decay of $B_c^{\ast +}(3S)\to B^{+}{D}^0$

Abstract

The decay constant for the vector state of $3S$-level in the heavy $(\bar{b}c)$-quarkonium is evaluated in the framework of sum rules for the mesonic currents. A scaling relation for the constants of vector quarkonia with different quark contents is derived. The numerical estime gives $\Gamma (B_c^{\ast +}(3S)\to B^{+}{D}^0)=90\pm 35$ MeV.

Comments: 6 pages, Revtex