Exploring $R_D$, $R_{D^{\ast }}$ and $R_{J\mathrm{/}\mathrm{\Psi }}$ anomalies

Deviations from the standard model predictions have been reported in various observables concerned with the lepton flavor universality. At present, the deviation of the measured values of $R_D$ and $R_{D^{\ast }}$ from the standard model expectation is exceeded by $2.3\sigma$ and $3.4\sigma$, respectively. Very recently LHCb has measured the ratio of branching ratio $R_{J/\Psi} = \mathcal B(B_c \to J/\Psi\tau\nu)/\mathcal B(B_c \to J/\Psi,l,\nu)$,where$l \in (e,,\mu)$,tobe$0.71\pm0.17\pm 0.18$whichisatmorethan$2\sigma$awayfromthestandardmodelprediction\mathrm{.}Weinvestigatetheanomaliesin$R_D$,$R_{D^{\ast}}$,and$R_{J/\Psi}$ using a model independent framework with minimal number of new physics couplings. We find various new physics models that can explain these anomalies within $1\sigma$.