T expansion of lowest hadron masses.

Abstract

We use the $t$-expansion method to calculate the hadronic spectrum of Hamiltonian lattice QCD with two massless dynamical quarks within the Kogut-Susskind formulation. We compute the energy density of the vacuum and the mass of the scalar ${0}^{++}$ state, which turns out to have about the same value as in the pure-glue calculation. We calculate the masses of the lowest-lying mesons, i.e., $\ensuremath{\rho}$, $\ensuremath{\omega}$, and $\ensuremath{\pi}$, and the nucleon. We show that the quark-antiquark component wins over the nucleon-antinucleon component of the meson in the crossover region. On the basis of an ${H}^{7}$ expansion we find the mesons to be degenerate. The high mass of the pion is due to the lack of continuous chiral symmetry in this model. The ratios of $\ensuremath{\omega}$ to $N$ masses are of the right magnitude.