A near-threshold enhancement in the Ds+Ds− system, dubbed as X(3960), is observed by the LHCb collaboration recently. A combined analysis on χc0(3930)(→D+D−), X(3960)(→Ds+Ds−), and X(3915)(→J/ψω) is performed using both a K-matrix approach of D(s)Dˉ(s) four-point contact interactions and a model of Flatt\'e-like parameterizations. The use of the pole counting rule and spectral density function sum rule indicate, under current statistics, that this Ds+Ds− near-threshold state has probably the mixed nature of a ccˉ confining state and Ds+Ds− continuum.
@article{arxiv.2302.06278,
title = {On the nature of X(3960)},
author = {Yu Chen and Hao Chen and Ce Meng and Hong-Rong Qi and Han-Qing Zheng},
journal= {arXiv preprint arXiv:2302.06278},
year = {2023}
}