Study of the Zc+ channel in lattice QCD

Abstract

Several charged charmonium-like hadrons called $Z_c$ have been recently discovered by different experiments. In contrast to conventional hadrons these contain at least two valence quarks and antiquarks ($\bar{c}c\bar{d}u$). We perform a lattice QCD simulation of the $I^G(J^{PC})=1^{+}(1^{+-})$ channel including all relevant two-meson operators under 4.3 GeV: $J/\psi \pi$, ${\psi }_{2S}\pi$, ${\psi }_{1D}\pi$, $D{\bar{D}}^{\ast }$, $D^{\ast }{\bar{D}}^{\ast }$, ${\eta }_c\rho$ as well as additional diquark anti-diquark operators. In our $N_f=2$ simulation with pion mass at 266 MeV we are able to identify all two-meson levels within the energy region of interest. However we find no additional level identifiable as a candidate for $Z_c$.

Comments: 7 pages, 3 figures, Contribution to the 32nd International Symposium on Lattice Field Theory (Lattice 2014), 23-28 June 2014, Columbia University, New York, NY, USA; updated references