# Beyond $R\left({D}^{\left(*\right)}\right)$ with the general type-III 2HDM for $b\to c\tau \nu$

Martinez, R. (Departamento de Física, Universidad Nacional de Colombia, Ciudad Universitaria, K. 45 No. 26-85, Bogotá D.C., Colombia) ; Sierra, C. F. (School of Physics and Astronomy, Monash University, Melbourne VIC-3800, Australia) ; Valencia, German (School of Physics and Astronomy, Monash University, Melbourne VIC-3800, Australia)

07 December 2018

Abstract: We review the parameter regions allowed by measurements of $R\left({D}^{\left(*\right)}\right)$ and by a theoretical limit on $B\left({B}_{c}\to \tau \nu \right)$ in terms of generic scalar and pseudoscalar new physics couplings, ${g}_{s}$ and ${g}_{p}$. We then use these regions as constraints to predict the ranges for additional observables in $b\to c\tau \nu$ including the differential decay distributions $d\Gamma /d{q}^{2}$; the ratios $R\left(J/\psi \right)$ and $R\left({\Lambda }_{c}\right)$; and the tau-lepton polarization in $B\to {D}^{\left(\star \right)}\tau \nu$, with emphasis on the $CP$-violating normal polarization. Finally we map the allowed regions in ${g}_{s}$ and ${g}_{p}$ into the parameters of four versions of the Yukawa couplings of the general type-III 2HDM model. We find that the model is still viable but could be ruled out by a confirmation of a large $R\left(J/\psi \right)$.

Published in: Physical Review D 98 (2018)