Constraints on the charged scalar effects using the forward-backward asymmetry on $B\to D^{(*)}τ\bar{ν_τ}$

Abstract

The decay modes $\bar{B}\to D^{(*)}τ\barν_τ$ are sensitive to charged scalar effects, such as the charged Higgs effects. In this paper we suggest a method to determine their effects by using the ratio of branching fractions and forward-backward asymmetries. In particular, forward-backward asymmetries on $\bar{B}\to D^{(*)}τ(\to πν_τ)\barν_τ$, $\bar{B}\to D^{(*)}τ(\to ρν_τ)\barν_τ$, and $\bar{B}\to D^{(*)}τ(\to a_1ν_τ)\barν_τ$ play an important role, which discriminate the Standard Model from other New Physics scenarios.