We present the first study of the charmonium spectrum using overlap fermions, on quenched configurations. Simulations are performed on 163×72 lattices, with Wilson gauge action at β = 6.3345. We demonstrate that we have discretization errors under control at about 5%. We obtain 88(4) MeV for hyperfine splitting using the r0 scale, and 121(6) MeV using the (1Pˉ−1Sˉ) scale. This paper raises the possibility that the discrepancy between the lattice results and the experimental value for charmonium hyperfine splitting can be resolved using overlap fermions to simulate the charm quark on lattice.
@article{arxiv.hep-lat/0507027,
title = {Charmonium Spectrum from Quenched QCD with Overlap Fermions},
author = {S. Tamhankar and A. Alexandru and Y. Chen and S. J. Dong and T. Draper and I. Horvath and F. X. Lee and K. F. Liu and N. Mathur and J. B. Zhang},
journal= {arXiv preprint arXiv:hep-lat/0507027},
year = {2008}
}