Hadron spectrum in QCD at6g2=5.6

Abstract

We have carried out a simulation of QCD using the hybrid-molecular-dynamics algorithm with two flavors of staggered quarks. The spectrum was calculated for $\frac{6}{g^2=5.6\mathrm{}}$ and dynamical quark masses ${\mathrm{am}}_q=0.025\mathrm{} \mathrm{and} 0.01$. Lattice sizes of ${12}^4$, ${12}^3$×24, and ${16}^4$ were used to generate the gauge configurations. Hadron propagators were calculated with both staggered and Wilson quarks on doubled or quadrupled latices. Finite-size effects are visible on the smaller lattices. Some improvement in the $\rho$-to-nucleon mass ratio and chiral symmetry is seen as compared to previous calculations, but, as in most lattice calculations, the proton-to-$\rho$ mass ratio remains larger than in the real world and the proton-$\Delta$ splitting is too small.