New physics effect on Bc→J/ψτν¯ in relation to the RD(⁎) anomaly

We study possible new physics (NP) effects on Bc→J/ψτν¯, which has been recently measured at LHCb as the ratio of RJ/ψ=B(Bc→J/ψτν¯)/B(Bc→J/ψμν¯). Combining it with the long-standing RD(⁎) measurements, in which the discrepancy with the prediction of the standard model is present, we find possible solutions to the anomaly by several NP types. Then, we see that adding the RJ/ψ measurement does not improve NP fit to data, but the NP scenarios still give better χ2 than the SM. We also investigate indirect NP constraints from the lifetime of Bc and NP predictions on the τ longitudinal polarization in B¯→D⁎τν¯.