PUBLISHED
We present a comprehensive study of the masses of pseudoscalar and vector mesons, as well as octet and decuplet baryons computed in O(a)-improved quenched lattice QCD. Results have been obtained using the nonperturbative definition of the improvement coefficient csw , and also its estimate in tadpole improved perturbation theory. We investigate effects of improvement on the incidence of exceptional configurations, mass splittings, and the parameter J. By combining the results obtained using nonperturbative and tadpole improvement in a simultaneous continuum extrapolation, we can compare our spectral data to experiment. We confirm earlier findings by the CP-PACS Collaboration that the quenched light hadron spectrum agrees with experiment at the 10% level.
This work was supported by the Particle Physics & Astronomy Research Council ~PPARC! through grants GR/L56336 and GR/L29927. We also acknowledge the support by EPSRC under grant GR/K41663. H.P.S. acknowledges the support of the Leverhulme foundation and the JSPS Research for the Future program. H.W. is grateful to Akira Ukawa for the hospitality at the Center of Computational Physics, University of Tsukuba, where part of this work was completed. D.G.R. and H.W. acknowledge the financial support of PPARC.