Speaker
Description
The BESIII Collaboration recently performed a precise measurement of the $e^+e^-\rightarrow D\bar{D}$ Born cross sections, and confirmed the $ G(3900) $ structure reported by BaBar and Belle with high significance. We identify the $ G(3900) $ as the first P-wave $D\bar{D}^{*}/\bar{D}D^*$ molecular resonance. The experimental and theoretical identification of the P-wave dimeson state holds paramount importance in enhancing our comprehension of the non-perturbative QCD and few-body physics. Its existence is firmly established in a unified meson-exchange model which simultaneously depicts the features of the $\chi_{c1}(3872)$, $ Z_c(3900) $ and $ T_{cc}(3875) $. The credibility of the investigations is also ensured by the fact that the P-wave interaction dominantly arises from the well-known long-range pion exchange. Additionally, thanks to the centrifugal barrier, it is easier to form resonances in P-wave than in S-wave. We extensively calculate all systems up to P-wave with various quantum numbers and predict a dense population of the $D\bar{D}^{*}/\bar{D}D^*$ and $DD^{*}$ states, where the S-wave $D\bar{D}^{*}/\bar{D}D^*$ state with $ I^G (J^{PC})=0^- (1^{+-})$, P-wave $D\bar{D}^{*}/\bar{D}D^*$ state with $ I^G(J^{PC})=0^+(0^{-+})$, and P-wave $DD^{*}$ state with $ I(J^P)=0(0^-) $ are more likely to be observed in experiments.
