$B$ anomalies in the nonminimal universal extra dimension model

Abstract

We investigate the $B$ anomalies in the framework of the nonminimal universal extra dimension models. Newly measured polarization parameters in $B\to D^{(\ast )}\tau \nu$, $P_{\tau }(D^{(\ast )})$ and $F_L(D^{\ast })$ as well as the ratios $R(D^{(\ast )})$ are considered altogether. The Kaluza-Klein modes of the $W$-boson and charged scalar contributes as the new physics effects. We find that the model parameters fit the global data very well with the minimum ${\chi }^2/d.o.f.$ near unity, rendering $B_c\to \tau \nu$ branching ratios to be a few percents. The best-fit values of $R(D)$ and $R(D^{\ast })$ are still far from ($\gtrsim 2\sigma$) the standard model predictions.

Comments: 19 pages, 8 figures; many improvements with more discussions and references; PRD accepted version