The annihilation decay B_c \to eta' l \nu

Abstract

We first investigate the semileptonic annihilation decay B_c \to \eta' l\nu in QCD. We find that the $\eta'$ momentum distribution is peaked within its small recoil region due to the loop effects. The branching ratio is estimated to be $ Br(B_c \to \eta' l\nu)=1.6\times 10^{-4}$ for $l=\mu,e$, which is accessible at CERN LHC.