The study of Ds1(2460) and Ds1(2536) mixing
  In this proceeding, we report our recent study of the mixing mechanism between $D_{s1}(2460)$ and $D_{s1}(2536)$. On the basis of Godfrey-Isgur model, we consider the $D^*K$ hadron loop effect on the ${}^3P_1$ and ${}^1P_1$ $c\bar{s}$ states. We construct the propagator matrix of these two-state system, from which we can extract the poles as well as the mixing angles. Through this method, we simultaneously determine the masses, widths and mixing angle of these two physical states and the results agree well with the experimental measurement. Besides the mass shift, we also find that the hadron loop effects can cause a significant shift for the mixing angles from the value determined in the heavy quark symmetry limit. 
Xiao-Gang Wu and Qiang Zhao
hep-ph