We present results of our numerical calculation of the mass spectrum for isospin one-half and spin one-half nonstrange baryons, i.e., the ground and excited states of the nucleon, in quenched lattice QCD. We use a new lattice discretization scheme for fermions, domain wall fermions, which possess almost exact chiral symmetry at nonzero lattice spacing. We make a systematic investigation of the negative-parity $N^{*}$ spectrum by using two distinct interpolating operators at $\beta {=6/g}^2=6.0\mathrm{}$ on a ${16}^3\times 32\times 16$ lattice. The mass estimates extracted from the two operators are consistent with each other. The observed large mass splitting between this state, $N^{*}\mathrm{}\left(1535\right),$ and the positive-parity ground state, the nucleon $N\left(939\right),$ is well reproduced by our calculations. We have also calculated the mass of the first positive-parity excited state and find that it is heavier than the negative-parity excited state for the quark masses studied.

• Received 26 February 2001

DOI:https://doi.org/10.1103/PhysRevD.65.074503