Dressed-quarks and the nucleon's axial charge
/ Authors
/ Abstract
qA, at infrared momenta. Since this effect disappears as chiral symmetry is restored, one may argue that gA vanishes with the restoration of chiral symmetry because no nucleon bound-state survives the associated transition. The suppression of g q A is shown to be part of an explanation for a 25% reduction of gA from its nonrelativistic quark-model value. Critical too, however, is the presence of dressed-quark angular momentum within the nucleon. The value of g q depends on the kernels of the gap and Bethe-Salpeter equations. We find that incorporation of essentially nonperturbative effects associated with DCSB into these kernels inflates the value relative to that obtained at leading-order in a widely used truncation of QCD’s Dyson-Schwinger equations. Such corrections also affect the nucleon’s axial radius. In both cases, however, agreement with experiment will require similar improvements to the Faddeev kernel and associated interaction current.
Journal: Physical Review C