Search for a $CP$-odd light Higgs boson in $J/\ddot{I}ˆ\to {\hat{I}}^3{A}^0$

Abstract

Using $J/\ddot{I}ˆ$ radiative decays from 9.0 billion $J/\ddot{I}ˆ$ events collected by the BESIII detector, we search for di-muon decays of a $CP$-odd light Higgs boson ($A^0$), predicted by many new physics models beyond the Standard Model, including the Next-to-Minimal Supersymmetric Standard Model. No evidence for the $CP$-odd light Higgs production is found, and we set $90\%$ confidence level upper limits on the product branching fraction $\mathcal{B}(J/\ddot{I}ˆ\to {\hat{I}}^3{A}^0)\times \mathcal{B}(A^0\to \hat{I}{¼}^{+}\hat{I}{¼}^{-})$ in the range of $(1.2-778.0)\times 10^{-9}$ for $0.212\le m_{A^0}\le 3.0$ GeV/$c^2$. The new measurement is a 6-7 times improvement over our previous measurement, and is also slightly better than the BaBar measurement in the low-mass region for $\tan {\hat{I}}^2=1$.

9 pages, 5 figures, accepted by Phys. Rev. D