Nucleon Resonances and Lattice QCD
Abstract
Lattice calculations provide an ab initio means for the study of QCD. Recent progress at understanding the spectrum and structure of nucleons from lattice QCD studies is reviewed. The talk begins with a brief introduction to the methodology of lattice spectroscopy calculations, focusing in particular on how the continuum symmetries of spin and parity are manifest in lattice calculations. Measurements of the masses of the lightest particles for the lowest spin values are presented and related to predictions of quark model and large-Nc approaches. The need to perform calculations at realistically light values of the pion mass is emphasised, and the exciting progress at attaining such masses is outlined. The determination of the masses of the higher resonances such as the Roper is described, and indications of their dramatic pion-mass dependence discussed. Finally, the rôle of multiquark states is addressed, and means for progress beyond the determination of the masses of the states to an understanding of their structure and partonic content described. The talk concludes with future prospects, capitalizing on the increasing effort of the US lattice community towards such fundamental issues in nuclear physics.
- Publication:
-
APS April Meeting Abstracts
- Pub Date:
- April 2003
- Bibcode:
- 2003APS..APR.H2002R