The semileptonic decays $B_c^{\ast }\to {\eta }_c\ell {\bar{\nu }}_{\ell }$ with QCD sum rules

Abstract

In this article, we calculate the $B_c^{\ast }\to {\eta }_c$ form-factors with the three-point QCD sum rules, then study the semileptonic decays $B_c^{\ast }\to {\eta }_c\ell {\bar{\nu }}_{\ell }$. The tiny decay widths may be observed experimentally in the future at the LHCb, while the $B_c^{\ast }\to {\eta }_c$ form-factors can be taken as basic input parameters in other phenomenological analysis.

Comments: 12 pages, 6 figures, slight revision