Possible Molecular Explanation for the Resonance Y (4500)

Abstract

The BESIII collaboration has discovered a new state with hidden charm-strange. Its mass is intriguingly close to the D-s(1968) (D) over bar (s1)(2536) threshold and does not have the properties of the charmonium states. Working with the QCD sum rules (QCDSR) approach, we test if the charmonium-like structure Y (4500), detected in the invariant mass spectrum K+K- J/psi may be interpreted as an exotic D-s (1968) (D) over bar (s1)(2536) molecular structure with J(PC) = 1(--). Considering the contributions of QCD condensates up to operator dimension ten, we estimate the mass and decay constant of Y (4500) resonance. We get m(Y) = (4488.35 +/- 11.54) MeV in excellent agreement with the meson mass reported by BESIII and f(Y) = (4.04 +/- 0.36) x 10(-3)GeV(4). Our findings indicate that a pseudoscalar-axialvector molecule current can well describe this state.