Signature of an $h_1$ state from $J/\psi \to \eta K^{\ast 0}{\bar{K}}^{\ast 0}$ and theoretical description of the $Z_c(3900)$ and $Z_c(4020)$ as $D{\bar{D}}^{\ast }$ and $D^{\ast }{\bar{D}}^{\ast }$ molecular states

Abstract

In this talk we address two topics: The first one is an empirical explanation in terms of a new state $h_1$ of the peak in the $K^{\ast 0}{\bar{K}}^{\ast 0}$ invariant mass distribution close to threshold of this channel in the $J/\psi \to \eta K^{\ast 0}{\bar{K}}^{\ast 0}$ decay. The second one is a theoretical description of the isospin $I=1$ $Z_c(3900)$ and $Z_c(4020)$ states in terms of molecular states of $D{\bar{D}}^{\ast }+cc$ and $D^{\ast }{\bar{D}}^{\ast }$.

Comments: Talk at the 13th International Workshop on Meson Production, Properties and Interaction KRAKÓW, POLAND, 29th May - 3rd June 2014