The rare semi-leptonic $B_c$ decays involving orbitally excited final mesons

Abstract

The rare processes $B_c\to D_{(s)J}^{(\ast )}\mu \bar{\mu }$, where $D_{(s)J}^{(\ast )}$ stands for the final meson $D_{s0}^{\ast }(2317)$, $D_{s1}(2460,2536)$,~$D_{s2}^{\ast }(2573)$, $D_0^{\ast }(2400)$, $D_1(2420,2430)$ or~$D_2^{\ast }(2460)$, are studied within the Standard Model. The hadronic matrix elements are evaluated in the Bethe-Salpeter approach and furthermore a discussion on the gauge-invariant condition of the annihilation hadronic currents is presented. Considering the penguin, box, annihilation, color-favored cascade and color-suppressed cascade contributions, the observables $\text{d}Br/\text{d}{Q}^2$, $A_{LPL}$, $A_{FB}$ and $P_L$ are calculated.