Particle theory

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 6g2=5.6 and dynamical quark masses amq=0.025 and 0.01. Lattice sizes of 124, 123×24, and 164 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 to-nucleon mass ratio and chiral symmetry is seen as compared to previous calculations, but, as in most lattice calculations, the proton-to mass ratio remains larger than in the real world and the proton splitting is too small. © 1990 The American Physical Society.

Abstract:

We describe a recent calculation of the hadron spectrum with two flavors of staggered dynamical quarks with a gauge coupling 6/g2 = 5.60 and quark masses of 0.025 and 0.01. The gauge fields were generated using the hybrid algorithm on a 124 lattice that was doubled or quadrupled to calculate hadron propagators. © 1990.

Abstract:

We present preliminary results on hadronic spectrum measurements by the High Energy Monte Carlo Grand Challenge (HEMCGC) collaboration. The simulation, on a 124 lattice, uses the hybrid molecular dynamics algorithm with two flavors of staggered fermions at two quark mass values and 6/g2 = 5.6. This measurement uses Wilson valence quarks at three values of the hopping parameter on a lattice that is doubled in the time direction. Our work allows a comparative study of these two types of lattice fermions at the parameters used, and provides a check on whether the continuum limit has been reached. The results exhibit the correct trends as the chiral limit is approached. © 1990.

Abstract:

We have carried out a simulation of quantum chromodynamics using the hybrid-molecular-dynamics algorithm with two flavors of Kogut-Susskind quarks. We have used Kogut-Susskind and Wilson valence quarks to calculate the hadron mass spectrum. Among our extensive results we discuss baryon hyperfine splitting, the nucleon-to- mass ratio, the sclar-to-tensor-glueball mass ratio, and the quantization and susceptibility of the topological charge. We have used a gauge coupling of 6/g2=5.60, and quark masses amq=0.025 and 0.01, in generating gauge configurations on 124, 123×24, and 164 lattices. © 1990 The American Physical Society.