Speaker
Description
The coupled channel scattering {D_s\bar{D}s,\, J/\psi \phi,\, D_s^{\ast}\bar{D}_s^{\ast}} involving a dip lineshape is studied in effective range expansion method in B\to D_s\bar{D}_s K, and sheds light on X_0(4140) spectrum. The X_0(4140) corresponds to a pole near J/\psi \phi threshold, where J/\psi \phi scattering length in single channel is (1.11\pm 0.65\,\rm{fm})
extracted, and an effective scattering length is (0.12^{+0.20}{-0.10}+i0.78^{+0.20}_{-0.40} \, \rm{fm}) in the coupled channel scattering. channel scattering. Assuming the spin interaction in J/\psi \phi scattering is negligible, a virtual state near the J/\psi \phi threshold in J^{PC}=1^{++} sector enhances the lineshape in J/\psi \phi invariant mass distribution, and plays a crucial role to pin down the puzzles in X_1(4140) widths. Heavy quark spin symmetry adapts a similar interaction to interpret a molecular \psi(2S)\phi state, X_1(4685). These three states provide a new way to probe OZI suppression in low-energy scattering.
