Exclusive weak B decays to excited meson states

Abstract

Exclusive semileptonic B decays to radially excited charmed mesons and rare radiative B decay to the orbitally excited tensor K_2^*(1430) meson are investigated in the framework of the relativistic quark model based on the quasipotential approach in quantum field theory. The heavy quark expansion is applied for the semileptonic B\to D^{(*)}'eνdecays. Both relativistic and the 1/m_Q corrections are found to play an important role for these decays and substantially modify results. For rare radiative B -> K_2^*(1430)γdecay such an expansion is not used for the s quark. Instead we apply the expansion in inverse powers of large recoil momentum of final K_2^*(1430) meson. The calculated branching fraction BR(B -> K_2^*(1430)γ)=(1.7\pm 0.6)\times 10^{-5} as well as the ratio BR(B -> K_2^*(1430)γ)/BR(B -> K^*(892)γ)=0.38\pm 0.08 are found to be in a good agreement with recent experimental data from CLEO.