Extractions of |Vub|/|Vcb| from a combined study of the exclusive bto u(c){ell}^{-}{overline{nu}}_{ell } decays

Abstract

We have extracted the ratio |Vub|/|Vcb| from a combined study of the available inputs on overline{B}to left(pi, rho, omega right){ell}^{-}{overline{nu}}_{ell } and overline{B}left({overline{B}}_sright)to left({D}^{left(ast right)},{D}_s^{left(ast right)}right){ell}^{-}{overline{nu}}_{ell } left(ell =mu textrm{or} eright) decays. We have done our analysis with and without the inclusion of the available experimental results on the branching fraction mathcal{BR}left({overline{B}}_sto {K}^{+}{mu}^{-}{overline{nu}}_{mu}right) or the ratio of the rates Gamma left({overline{B}}_sto {K}^{+}{ell}^{-}{overline{nu}}_{ell}right)/Gamma left({overline{B}}_sto {D}_s^{+}{ell}^{-}{overline{nu}}_{ell}right) . We have used all the available experimental data on the branching fractions in different q2-bins, the available theory inputs on the form factors from lattice and the light cone sum rule (LCSR) approach; analysed the data in different possible scenarios and presented the results. From a combined analysis of all the b → cℓ−νℓ exclusive decays, we have obtained |Vcb| = (40.5 ± 0.6) × 10−3 and from all the b → uℓ−νℓ modes, we obtain |Vub| = (3.46 ± 0.12) × 10−3 which changes to |Vub| = (3.51 ± 0.13) × 10−3 after dropping mathcal{BR}left({overline{B}}_sto {K}^{+}{mu}^{-}{overline{nu}}_{mu}right) . We hence report the values of the ratio |Vub|/|Vcb| = 0.085 ± 0.003 and 0.087 ± 0.003 with and without the input from {overline{B}}_sto {K}^{+}{mu}^{-}{overline{nu}}_{mu } modes, respectively. We have also predicted the ratio Gamma left({overline{B}}_sto {K}^{+}{ell}^{-}{overline{nu}}_{ell}right)/Gamma left({overline{B}}_sto {D}_s^{+}{ell}^{-}{overline{nu}}_{ell}right) using the fit results. In addition, we provide the predictions of mathcal{BR}left({overline{B}}_sto {K}^{+}{mu}^{-}{overline{nu}}_{mu}right) and mathcal{BR}left(overline{B}to left(rho, omega right){ell}^{-}{overline{nu}}_{ell}right) in the Standard Model (SM) in small q2-bins.