2025/05/30 by Li, Geng, Shi, Chunjiang, Chen, Ying +1
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat)
paper · doi:10.48550/arxiv.2505.24213
The S-wave scattering amplitudes of J/ψJ/ψ with quantum numbers JPC = 0++ and 2++ are determined up to 6600 MeV using lattice QCD calculations at mπ≈ 420 and 250 MeV. The 1S0 J/ψJ/ψ system exhibits a near-threshold attractive interaction, resulting in a virtual bound state with a binding energy of approximately 30-40 MeV. In contrast, the 5S2 J/ψJ/ψ system exhibits a repulsive interaction near threshold. These behaviors are primarily dominated by the quark rearrangement effect. Most notably, a resonance is observed in the 5S2 J/ψJ/ψ channel, with a mass around 6540 MeV and a width of approximately 540 MeV. The extracted mass and width are consistent with the X(6600) (or X(6400)) observed by the ATLAS and CMS collaborations, and show little dependence on the sea pion mass.