Y(4260) on the lattice

TL;DR

This lattice QCD study investigates the mass spectra of exotic charmonium states, identifying a resonance consistent with Y(4260) and predicting heavier exotic mesons with specific quark contents.

Contribution

The paper provides the first lattice QCD evidence for the Y(4260) resonance and explores the mass spectrum of various exotic charmonium-like states using quenched lattice simulations.

Findings

Resonance around 4238 MeV identified with Y(4260)

Heavier exotic mesons with specific quark content predicted

Masses of exotic states measured with uncertainties

Abstract

We investigate the mass spectra of closed-charm mesons with $ J^{PC} = 1^{--} $, for hybrid charmonium, molecules, and diquark-antidiquark operators, in quenched lattice QCD with exact chiral symmetry. For two lattice volumes $ 24^3 \times 48 $ and $ 20^3 \times 40 $, each of 100 gauge configurations generated with single-plaquette action at $ \beta = 6.1 $, we compute point-to-point quark propagators and measure the time-correlation functions of these exotic meson operators. For the molecular operator $ \{(\qbar\gamma_5\gamma_i\c)(\cbar\gamma_5\q)- (\cbar\gamma_5\gamma_i\q)(\qbar\gamma_5\c) \} $, it detects a resonance with mass around $ 4238 \pm 31 $ MeV, which is naturally identified with $ Y(4260) $. Further, for any molecular and diquark-antidiquark operator, it detects heavier exotic charmed mesons, with quark content $ (\c\s\cbar\sbar) $ around $ 4450 \pm 100 $ MeV, and $ (\c\c\cbar\cbar) $ around $ 6400 \pm 50 $ MeV.