Search for Z_c^+(3900) in the 1^+- channel on the lattice

TL;DR

This study searches for the exotic Z_c^+(3900) state in lattice QCD simulations with specific quantum numbers but finds only scattering states, suggesting the need for further investigation with more diverse interpolators.

Contribution

The paper provides the first lattice QCD search for Z_c^+(3900) in the 1^+- channel, highlighting limitations and proposing future directions.

Findings

No candidate Z_c^+(3900) found in the 1^+- channel

Detected only D D* and J/psi pi scattering states

Additional interpolators needed for conclusive results

Abstract

Recently three experiments reported a discovery of manifestly exotic Z_c^+(3900) in the decay to J/psi pi+, while J and P are experimentally unknown. We search for this state on the lattice by simulating the channel with J^PC=1^+- and I=1, and we do not find a candidate for Z_c^+(3900). Instead, we only find discrete scattering states D D* and J/psi pi, which inevitably have to be present in a dynamical QCD. The possible reasons for not finding $Z_c^+$ may be that its quantum numbers are not $1^{+-}$ or that the employed interpolating fields are not diverse enough. Simulations with additional types of interpolators will be needed to reach a more definite conclusion.