N* Mass Spectrum from an Anisotropic Action

TL;DR

This paper reports on the calculation of N* baryon mass spectra in specific spin-parity sectors using anisotropic lattice QCD, observing clear mass splittings consistent with experimental data.

Contribution

It introduces a lattice QCD approach with tadpole-improved actions to accurately determine excited N* states and their splittings.

Findings

Observed clear mass splittings from the nucleon ground state.

Isolated first excited states using correlation matrix and variational method.

Results are consistent with experimental observations.

Abstract

Results are reported for N* masses in the 1/2+ and 1/2- sectors on an anisotropic lattice. The gauge action is the usual plaquette plus rectangle type, the quark action is of the D234 type, both having tadpole-improved tree-level coefficients. Clear splittings from the nucleon ground state are observed with smeared operators and 500 configurations. The first excited states in each channel are further isolated, using a correlation matrix and the variational method. The basic pattern of these splittings is consistent with experimental observations.