Study of the Y(4660) from a light-quark perspective

In this paper, we try to reveal the structure of the Y(4660) from the light-quark perspective. We study the dipion invariant mass spectrum and the helicity angular distributions of the e(+)e(-) -> Y(4660) -> psi(2S)pi(+)pi(-) process. In particular, we consider the effects of different light-quark SU(3) eigenstates inside the Y(4660). The strong pion-pion final-state interactions as well as the K (K) over bar coupled channel in the S-wave are taken into account model independently by using dispersion theory. We find that the light-quark SU(3) octet state plays a significant role in this transition, implying that the Y(4660) contains a large lightquark component and thus might not be a pure conventional charmonium state. In the fit scheme considering both the SU(3) singlet and SU(3) octet states, two solutions are found, and both solutions reproduce the pi pi invariant-mass spectra well. New measurement data with higher statistics in the future will be helpful to better distinguish these two solutions.

Automated summary

This paper investigates the structure of the Y(4660) from a light-quark perspective, revealing a significant light-quark component in the transition and suggesting it may not be a pure conventional charmonium state. Two solutions considering both the SU(3) singlet and SU(3) octet states reproduce the pi pi invariant-mass spectra well, with new measurement data needed for better distinction between the solutions in the future.