$ÏNN$ and Pseudoscalar Form Factors from Lattice QCD

K. F. Liu; S. J. Dong; Terrence Draper; Walter Wilcox

doi:10.1103/PhysRevLett.74.2172

paper

$I ¨ N N$ and Pseudoscalar Form Factors from Lattice QCD

arXiv:hep-lat/9406007 · doi:10.1103/PhysRevLett.74.2172

Abstract

The $I ¨ N N$ form factor $g_{I ¨ N N} (q^{2})$ is obtained from a quenched lattice QCD calculation of the pseudoscalar form factor $g_{P} (q^{2})$ of the proton with pion pole dominance. We find that $g_{I ¨ N N} (q^{2})$ fitted with the monopole form agrees well with the Goldberger-Treiman relation and is much preferred over the dipole form. The monopole mass is determined to be $0.75 \pm 0.14 GeV$ which shows that $g_{I ¨ N N} (q^{2})$ is rather soft. The extrapolated $I ¨ N$ coupling constant $g_{I ¨ N N} = 12.7 \pm 2.4$ is quite consistent with the phenomenological values. We also compare $g_{I ¨ N N} (q^{2})$ with the axial form factor $g_{A} (q^{2})$ to check the pion dominance in the induced pseudoscalar form factor $h_{A} (q^{2})$ vis Ã vis chiral Ward identity.

8 pages of text plus 4 postscript figures (128 kbytes)

I¨NN and Pseudoscalar Form Factors from Lattice QCD

Abstract

$I ¨ N N$ and Pseudoscalar Form Factors from Lattice QCD