arXiv subjects
Publications and source records attributed to R. Altmeyer.
We report on calculations of the hadronic coupling constants $g_{ρππ}$ and $g_{nnπ}$ based on lattice QCD with four flavors of dynamical staggered fermions. By computing 2--point and 3--point Green's functions we have been able to determine these coupling constants ab initio from QCD; the results are compatible with the experimental values.
A lattice calculation of the pi-N sigma term is described using dynamical staggered fermions. Preliminary results give a sea term comparable in magnitude to the valence term.
We will discuss here an indirect lattice evaluation of the baryon axial singlet current matrix element. This quantity may be related to the fraction of nucleon spin carried by the quarks. The appropriate structure function has recently been measured (EMC experiment). As in this experiment, we find that the quarks do not appear to carry a large component of the nucleon spin.
A lattice calculation of the pi-N sigma term is described using dynamical staggered fermions. Preliminary results give a sea term comparable in magnitude to the valence term.
The fraction of the nucleon spin that is carried by the quarks, $ΔΣ$, is computed in lattice QCD with dynamical staggered fermions. We obtain the value $ΔΣ= 0.18 \pm 0.02$.
A numerical calculation of the lattice staggered renormalisation constants at $β= 5.35$, $m = 0.01$ is presented. It is seen that there are considerable non-perturbative effects present. As an application the vector decay constant $f_ρ$ is estimated. (LAT92 contribution, one LATEX file with 3 postscript figures appended.)