Physics

Isovector

Lattice field theory

Particle physics

Quantum chromodynamics

Gluon

Nucleon

Acoustics

Nuclear physics

Helicity

Lattice (music)

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Proceedings of The XXVII International Symposium on Lattice Field Theory — PoS(LAT2009)

We report lattice-volume independence of low moments of nucleon structure functions from the coarse RIKEN-BNL-Columbia (RBC) and UKQCD joint dynamical (2+1)-flavor domain-wall fermions (DWF) ensembles at the lattice cut off of a -1 ∼ 1.7 GeV.The isovector quark momentum fraction, x u-d , and helicity fraction, x ∆u-∆d , both fully non-perturbatively renormalized are studied on two spatial volumes of (∼ 2.7fm) 3 and (∼ 1.8fm) 3 .Their naturally renormalized ratio, x u-d / x ∆u-∆d , is not affected by any finite-size effect.It does not depend strongly on light quark mass and does agree well with the experiment.The respective absolute values, fully non-perturbatively renormalized, do not show any finite-size effect either.They show trending toward the respective experimental values at the lightest up-and down-quark mass.This trending down to the experimental values appears to be a real physical effect driven by lighter quarks.The observations are in contrast to the huge finite-size effect seen in the axial-current form factors.

Nucleon structure functions from dynamical (2+1)-flavor domain wall fermions