Phenomenology analysis of $$\bar{B}^* \rightarrow V \tau ^-\bar{\nu }_{\tau }$$ decays in and beyond the Standard Model

Abstract

AbstractMotivated by the persistent anomalies reported in the $$b\rightarrow c \tau \bar{\nu }$$ b → c τ ν ¯ data, we investigate the semileptonic decays $$\bar{B}^* \rightarrow V \tau ^-\bar{\nu }_{\tau } (V=D^*_{u,d,s},J/\psi )$$ B ¯ ∗ → V τ - ν ¯ τ ( V = D u , d , s ∗ , J / ψ ) , within the Standard Model and beyond. The relevant transition form factors, being calculated in the covariant light-front quark model, is the main source of theoretical uncertainties. Using various best-fit solutions for the new operator Wilson coefficients, we report numerical results on various observables related to the processes $$\bar{B}^* \rightarrow V \tau ^-\bar{\nu }_{\tau }$$ B ¯ ∗ → V τ - ν ¯ τ , such as the branching ratios, the ratio of branching fractions, the hadron and lepton polarization asymmetries, the forward–backward asymmetries and the convexity parameter. We also predict the $$q^2$$ q 2 distribution of these observables both within the Standard Model and in various new physics scenarios. The accessible observables are studied in order to assess their sensitivity to the different new physics scenarios. We can find that some of the new physics scenarios can be differentiated from each other by using these observables and their correlations. We also find that some observables of these decay modes are sizeable and deviate significantly (for new physics coupling parameter $$S_R$$ S R especially) from their corresponding standard model values, which are expected to be within the reach of Run III of Large Hadron Collider experiment. And experimental information on these distributions which will be testified in the future can help to disentangle the dynamical origin of the current anomalies.