Comment on Implications of new physics in the decays $B_c\to (J/\psi ,{\eta }_c)\tau \nu$

Abstract

As part of a study BSM corrections to leptonic decays of the $B_c$ meson, Tran et al. (arXiv:1801.06927) use the covariant confining quark model (CCQM) to estimate the matrix element of the pseudo-scalar curent between the vacuum and the $B_c$ meson. We note that this matrix element can be determined using existing lattice QCD results.

Comments: 3 pages. No figures