Speaker
Yun-Hua Chen
(University of Science and Technology Beijing)
Description
In this work, we try to gain insights into the structure of the $Y(4260)$ from the light-quark perspective.
We study the dipion invariant mass spectrum of the $e^+ e^-
\to Y(4260) \to J/\psi \pi^+\pi^-$ process and the ratio of the cross sections
${\sigma(e^+e^- \to J/\psi K^+ K^-)}/{\sigma(e^+e^- \to J/\psi \pi^+\pi^-)}$. In
particular, we consider the effects of different light-quark SU(3)
eigenstates inside the $Y(4260)$. The strong pion--pion final-state interactions
as well as the $K\bar{K}$ coupled channel in the $S$-wave
are taken into account in a model-independent way using dispersion
theory. We find that the SU(3) octet state plays a significant
role in these transitions, implying that the $Y(4260)$ contains a
large light-quark component.
Our findings suggest that the $Y(4260)$ is neither a hybrid nor a conventional charmonium state, and they are consistent with the $Y(4260)$ having a sizeable $\bar D D_1$ component which, however, is not completely dominant.
Primary author
Yun-Hua Chen
(University of Science and Technology Beijing)
