A possible signature of new physics at BES-III

Abstract

The recent observations of the purely leptonic decay $\text{Ds}\to {\mu }^{+}{\nu }_{\mu }$ and ${\tau }^{+}{\nu }_{\tau }$ at CLEO-c and $B$ factory may allow a possible contribution from a charged Higgs boson. One such measurement of the decay constant $f_{D_s}$ differs from the most precise unquenched lattice QCD calculation by 4 $\sigma$ level. Meanwhile, the measured ratio, $\mathcal{B}\mathcal{R}(\text{Ds}\to {\mu }^{+}{\nu }_{\mu })$ / $\mathcal{B}\mathcal{R}(\text{Dp}\to {\mu }^{+}{\nu }_{\mu })$, is larger than the standard model prediction at 2.0$\sigma$ level. We discuss that the precise measurement of the ratio $\mathcal{B}\mathcal{R}(\text{Ds}\to {\mu }^{+}{\nu }_{\mu })$ / $\mathcal{B}\mathcal{R}(\text{Dp}\to {\mu }^{+}{\nu }_{\mu })$ at BES-III will shed light on the presence of new intermediate particles by comparing the theoretical predictions, especially, the predictions of high precise unquenched lattice QCD calculation.

Comments: 5 pages, 3 figures, mini-review, accepted by Chinese Physics C (HEP & NP)