by BELLE Collaboration and it is reported to be $P_{\tau}^{D^{\ast}} = -0.38\pm 0.51^{+0.21}_{-0.16}$. All these measurements indicate an upward deviation from the SM expectation.

Various model-independent and model-dependent [@Fajfer1; @Tanaka:1994ay; @Nierste:2008qe; @miki; @Crivellin; @datta; @datta1; @datta2; @fazio; @Celis; @He; @dutta; @Deshpand:2016cpw; @Li:2016vvp; @Bardhan:2016uhr; @Alok:2016qyh; @Ivanov:2015tru; @Ivanov:2016qtw; @Nandi:2016wlp; @Dutta:2016eml; @Alonso:2016oyd; @Celis:2016azn; @Altmannshofer:2017poe; @Iguro:2017ysu] approaches have been carried out to explore NP effects in $R_D$ and $R_{D^{\ast}}$. Very recently, NP effects on $B_c \to J/\Psi\,\tau\nu$ decays has also been studied by various authors [@Dutta:2017xmj; @Watanabe:2017mip; @Chauhan:2017uil]. In view of the new measurement of $R_{J/\Psi}$ made by LHCb, we investigate $R_D$, $R_{D^{\ast}}$, and $R_{J/\Psi}$ anomalies within a model independent framework with minimal number of NP couplings. We use the most general effective Lagrangian in the presence of NP which is valid at renormalization scale $\mu = m_b$ and seek to find the minimal number of NP couplings that best fit the data. We have considered total $55$ NP scenarios based on NP contributions from single operators as well as from two different operators and try to find the scenario that best explains $R_D$, $R_{D^{\ast}}$, and $R_{J/\Psi}$ anomalies. Although this is not entirely a new idea, most efforts at explaining these anomalies consider only 