arXiv subjects
Publications and source records attributed to Jiangchuan Chen.
We present recent BESIII results about the study of mesons which contain at least one charm quark. We determined the D(s)+ decay constants, the form factors of D semi-leptonic decays, the CKM matrix elements |Vcs(d)|.
Using 58 million $J/ψ$ decays, we have investigated the $p \bar{p}$ invariant mass spectrum in the radiative decay $J/ψ\to γp \bar{p}$ and observe a prominent structure with mass near $2m_p$. Fitting with an S-wave Breit-Wigner, we obtain a peak mass of $M= 1859^{+3}_{-10}(\rm stat)^{+5}_{-25}(sys) MeV/c^2$. $J/ψ\to γη_c$ decays from the same sample are used to determine the mass, width, and hadronic branching ratios of the $η_c$. From a sample of 14 million $ψ(2S)$ events, the first observation of $χ_{cJ}$ (J=0,1,2) decays to $Λ\barΛ$ is made, and branching ratios are determined, which are larger than expected from the Color Octet Model. Branching ratios of $K_s^0K_L^0$ in both $ψ(2S)$ and $J/ψ$ decays are measured, and a more than four sigma deviation from the pQCD predicted "12% rule" is observed. In $ψ(3770)$ decays, evidence for the non-$D\bar{D}$ decay to $π^+π^-J/ψ$ is observed.