Production ofY(4260)as a hadronic molecule state ofD¯D

Abstract

We study the Y (4260) production mechanism in e + e − annihilations in the framework of hadronic molecules and investigate the consequence of such a picture in different decay channels. In the hadronic molecule picture the Y (4260) is described as a mixture state composed of a long-ranged DD1(2420) + c.c. molecule state and a compact cc component. We show that the compositeness relation can still provide a reasonable constraint on the wavefunction renormalization parameter due to the dominance of the molecular component. Such a mechanism can be regarded as a natural consequence of the heavy quark spin symmetry (HQSS) breaking. This study elaborates the molecular picture for the Y (4260) in the e + e − annihilations and affirms that the cross section lineshape of e + e − →DD * π + c.c. in the vicinity of the Y (4260) should have a nontrivial behavior. In this framework we predict that the upper limit of the Y (4260) leptonic decay width is about 500 eV. We also investigate the coupling for D1(2420) → D * π in the 3 P0 quark model and examine the possible HQSS breaking effects due to the deviation from the | 1 P1 and | 3 P1 ideal mixing. This will in turn provide a constraint on the HQSS breaking coupling for the Y (4260) toDD1(2420) + c.c. via its cc component.

Resonant parameters of the Y(4220)

“…The recent estimate of Lattice QCD (LQCD) for the leptonic decay width of the Y (4220) is about 40 eV [31] as a feature of the hybrid scenario; the predicted upper limit of the Y (4220) leptonic decay width is about 500 eV if the Y (4220) is a hadronic molecule dominated by DD 1 (2420) [32]; the leptonic decay width is only about 23 eV for the ωχ c0 molecule interpretation [33] where no contributions from the open charm decay channel are included in the analysis.…”

Threshold and Kinematic Effects for the Exotic Resonance-Like Structures

“…In a series of recent works it was shown that theDD 1 (2420) + c.c. molecular scenario is favored by the study of cross section lineshapes in those exclusive channels [27][28][29][30][31][32]36]. In particular, the nature of Y(4260) as theDD 1 (2420) + c.c.…”

“…As shown in Refs. [30,31] the existence of theDD 1 (2420) + c.c. molecular component can be probed by the cross section lineshapes of exclusive reaction channels in e + e − annihilations.…”

Probing Y(4260) as the \(\bar{D}D_{1} + c.c.\) Hadronic Molecule State in e+e− Annihilations

“…[15] the angular distribution of the pion in the e + e − c.m. frame with respect to the beam axis is extremely interesting.…”

“…Angular distribution of the recoiled pion in the e + e − c.m. frame with respect to the beam axis [15]. The data are from Ref.…”