⟨x⟩u-d from lattice QCD at nearly physical quark masses

We determine the second Mellin moment of the isovector quark parton distribution function < x >(u-d) from lattice QCD with N-f = 2 sea quark flavors, employing the nonperturbatively improved Wilson-Sheikholeslami-Wohlert action at a pseudoscalar mass m(pi) = 157(6) MeV. The result is converted nonperturbatively to the RI'-MOM scheme and then perturbatively to the MS scheme at a scale mu = 2 GeV. As the quark mass is reduced we find the lattice prediction to approach the value extracted from experiments.