Double-charm and hidden-charm hexaquark states under the complex scaling method

Abstract

We investigate the double-charm and hidden-charm hexaquarks as molecules in the framework of the one-boson-exchange potential model. The multichannel coupling and S − D wave mixing are taken into account carefully. We adopt the complex scaling method to investigate the possible quasibound states, whose widths are from the three-body decay channel ΛcΛcπ or Λc Λcπ. For the double-charm system of I(J P ) = 1(1 + ), we obtain a quasibound state, whose width is 0.50 MeV if the binding energy is -14.27 MeV. And the S-wave ΛcΣc and ΛcΣ * c components give the dominant contributions. For the 1(0 + ) double-charm hexaquark system, we do not find any pole. We find more poles in the hidden-charm hexaquark system. We obtain one pole as a quasibound state in the I G (J P C ) = 1 + (0 −− ) system, which only has one channel (Λc Σc + Σc Λc)/ √ 2. Its width is 1.72 MeV with a binding energy of -5.37 MeV. But, we do not find any pole for the scalar 1 − (0 −+ ) system. For the vector 1 − (1 −+ ) system, we find a quasibound state. Its energies, widths and constituents are very similar to those of the 1(1 + ) double-charm case. In the vector 1 + (1 −− ) system, we get two poles-a quasibound state and a resonance. The quasibound state has a width of 0.6 MeV with a binding energy of -15.37 MeV. For the resonance, its width is 2.72 MeV with an energy of 63.55 MeV relative to the Λc Σc threshold. And its partial width from the two-body decay channel (Λc Σc − Σc Λc)/ √ 2 is apparently larger than the partial width from the three-body decay channel Λc Λcπ. Especially, the 1 + (0 −− ) and 1 − (1 −+ ) hidden-charm hexaquark molecular states are very interesting. These isovector mesons have exotic J P C quantum numbers which are not accessible to the conventional q q mesons. ( * ) c and Λ c Σ( * ) c channels in the molecule picture. As pointed out in our previous work [61], the cross diagram DD * ↔ D * D of the one-pion-exchange will provide a complex potential, which is from the three-body decay effect. This behavior

Explanation of Y(4630) as a hadronic resonant state*

“…[30], the authors first extend the CSM from atomic, molecular, and nuclear physics to hadron physics to explain the hadron molecular state. Recently, the CSM has been increasingly used in hadronic physics [31][32][33].…”