Identification of the G(3900) Structure as the P -Wave DD¯*/D¯D* Resonance

The BESIII Collaboration recently performed a precise measurement of the e+e−→DD¯ Born cross sections, and confirmed the G(3900) structure reported by and Belle with high significance. We identify the G(3900) as the first P-wave DD¯*/D¯D* molecular resonance. The experimental and theoretical identification of the P-wave dimeson state holds paramount importance in enhancing our comprehension of the nonperturbative QCD and few-body physics. Its existence is firmly established in a unified meson-exchange model that simultaneously depicts the features of the χc1(3872), Zc(3900), and Tcc(3875). This scenario can be directly examined in the e+e−→DD¯*/D¯D* cross section by seeing whether a resonance exists at the threshold. 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 DD¯*/D¯D* and DD* states, where the S-wave DD¯*/D¯D* state with IG(JPC)=0−(1+−), P-wave DD¯*/D¯D* state with IG(JPC)=0+(0−+), and P-wave DD* state with I(JP)=0(0−) are more likely to be observed in experiments. Published by the American Physical Society 2024