出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report isovector form factors and low moments of isovector structure functions of nucleon
from the coarse RIKEN-BNL-Columbia (RBC) and UKQCD joint dynamical (2+1)-flavor
domain-wall fermions (DWF) ensembles. The lattice cut off is estimated at a1 = 1:7 GeV. The
lattice volume is as large as 2.7 fm across. The dynamical strange mass is set at slightly heavier
than physical, and degenerate up and down mass is varied correpsonding to pion mass of about
0.67, 0.56, 0.42 and 0.33 GeV. We carefully optimize the nucleon source/sink separation in time
to about 1.4 fm. Unexpectedly large finite-size effect in the axial charge is found. The effect
scales with a single variable, the product mpL of the pion mass mp and lattice spatial linear extent
L, and sets in at around mpL = 5. We also discuss momentum-transfer dependence of the
vector, induced tensor, axial-vector and induced pesudo-scalar form factors. In particular we extract
Dirac and Pauli mean-squared charge radii, magnetic moment, pNN coupling constant and
pseudoscalar coupling gP of muon capture by nucleon. While the mean-squared charge radii
are distant from the respective experiments, the other observables are in reasonable agreement
with the experiments. From structure functions, fully non-perturbatively renormalized iso-vector
quark momentum fraction, hxiud, helicity fraction, hxiDuDd, and transversity, h1idudd, are reported,
as well as an unrenormalized twist-3 coefficient, d1. The ratio of the momentum to helicity
fractions, hxiud=hxiDuDd, does not depend on light quark mass and agree well with the experiment.
Their respective absolute values, fully renormalized, shows interesting trending toward the
respective experimental values at the lightest light quark mass.
