Speaker
Si-Run Xue
(Institute of High Energy Physics, Chinese Academy of Sciences)
Description
During the past decade, a large number of the so-called $X$, $Y$, $Z$ states have been observed in the heavy flavor sector, as have become candidates for exotic hadrons which may contain more complicated quark-gluon structures than the conventional quark model picture. Among all those exotic candidates, the $Y(4260)$ is undoubtedly one of the most mysterious states and has initiated a lot of experimental and theoretical studies since its observation by BaBar Collaboration in the $J/\psi\pi\pi$ channel in 2005. I will discuss our recent works in probing $Y(4260)$ as the $D_1\bar{D}+c.c.$ hadronic molecule state using the non-relativistic effective field theory. This study shows that the $Y(4260)$ contains predominantly a $\bar{D}D_1+c.c.$ molecular component and its decays into the $\bar{D}D^*\pi+c.c.$ channel should have a nontrivial lineshape. It also provides a natural explanation for the production of $Y(4260)$ in $e^+e^-$ annihilations in the same framework and allows us to predict the $Y(4260)$ leptonic decay width of which the upper limit is about 500 eV.
