Excited Baryons in Lattice QCD
Abstract
We present first results for the masses of positive and negative parity excited baryons calculated in lattice QCD using an O(a^2)-improved gluon action and a fat-link irrelevant clover (FLIC) fermion action in which only the irrelevant operators are constructed with APE-smeared links. The results are in agreement with earlier calculations of N^* resonances using improved actions and exhibit a clear mass splitting between the nucleon and its chiral partner. An correlation matrix analysis reveals two low-lying J^P=(1/2)^- states with a small mass splitting. The study of different Lambda interpolating fields suggests a similar splitting between the lowest two Lambda1/2^- octet states. However, the empirical mass suppression of the Lambda^*(1405) is not evident in these quenched QCD simulations, suggesting a potentially important role for the meson cloud of the Lambda^*(1405) and/or a need for more exotic interpolating fields.
Cite
@article{arxiv.hep-lat/0202022,
title = {Excited Baryons in Lattice QCD},
author = {W. Melnitchouk and S. Bilson-Thompson and F. D. R. Bonnet and F. X. Lee and D. B. Leinweber and A. G. Williams and J. M. Zanotti and J. B. Zhang},
journal= {arXiv preprint arXiv:hep-lat/0202022},
year = {2010}
}
Comments
Correlation matrix analysis performed. Increased to 400 configurations. 22 pages, 13 figures, 15 tables