QCD sum rules study of the image charmonium Y mesons Original Research Article

We use QCD sum rules to test the nature of the recently observed mesons Y(4260), Y(4350) and Y(4660), assumed to be exotic four-quark View the MathML source or View the MathML source states with JPC=1−−. We work at leading order in αs, consider the contributions of higher dimension condensates and keep terms which are linear in the strange quark mass ms. We find for the View the MathML source state a mass mY=(4.65±0.10) GeV which is compatible with the experimental candidate Y(4660), while for the View the MathML source state we find a mass mY=(4.49±0.11) GeV, which is still consistent with the mass of the experimental candidate Y(4350). With the tetraquark structure we are working we cannot explain the Y(4260) as a tetraquark state. We also consider molecular View the MathML source and View the MathML source states. For the View the MathML source molecular state we get View the MathML source which is consistent, considering the errors, with the mass of the meson Y(4350) and for the View the MathML source molecular state we get View the MathML source in excellent agreement with the mass of the meson Y(4260).