Probing New Physics in Light of Recent Developments in b → c ℓ v Transitions

Abstract

Abstract Experimental studies of the observables associated with $b \rightarrow c$ transitions in semileptonic B-meson decays at BaBar, Belle, and LHCb have shown some deviations from the Standard Model predictions, consequently providing a handy tool to probe the possible new physics (NP). In this context, we first revisit the impact of recent measurements of $R({D^{(*)}})$ and $R(\Lambda _c)$ on the parametric space of the NP scenarios. In addition, we include the $R(J/\psi )$ data in the analysis and find that their influence on the best-fit point and the parametric space is mild. Using the recent HFLAV data, after validating the well established sum rule of $R(\Lambda _c)$, we derive a similar sum rule for $R(J/\psi )$. Furthermore, according to the updated data, we modify the correlation among the different observables, giving us their interesting interdependence. Finally, to discriminate the various NP scenarios, we plot the different angular observables and their ratios for $B \rightarrow D^{*} \tau \nu _\tau$ against the transfer momentum square $\left(q^2\right)$, using the $1\sigma$ and $2\sigma$ parametric space of considered NP scenarios. By implementing the collider bounds on NP Wilson coefficients (WCs), we find that the parametric space of some NP WCs is significantly restrained. To see the clear influence of NP on the amplitude of the angular observables, we also calculate their numerical values in different $q^2$ bins and show them through bar plots. We hope that their precise measurements will help to discriminate various NP scenarios.