Heavy quark spin partners of the $Y(4260)$ in coupled-channel formalism

Abstract

The charmoniumlike state Y(4260) is described as predominantly a D 1 D molecule in a coupled-channel quark model [Phys. Rev. D 96, 114022 (2017)]. The heavy quark spin symmetry (HQSS) thus implies the possible emergence of its heavy quark spin partners with molecular configuration as D 1 D * and D * 2 D * below these charmed mesons' thresholds. We analyze the probabilities of various intermediate charmed meson loops for J PC = 1 −− exotic state Y(4360) and find that the channel D 1 D * couples more strongly around its mass regime, and the coupling behavior remains the same even if the mass of Y(4360) is pushed closer to D 1 D * threshold. This enlightens that the most favorable molecular scenario for the Y(4360) could be D 1 D * , and hence it can be interpreted as HQSS partner of the Y(4260). We also find the strong coupling behavior of D * 2 D * channel with the ψ(4415), which makes it a good candidate for a dominant D * 2 D * molecule. We discuss the important decay patterns of these resonances to disentangle their long-and short-distance structures.