Mass Effects on the Nucleon Sea Structure Functions

Nucleon sea structure functions are studied using Dokshitzer-Gribov-Lipatov-AltarelliParisi (DGLAP) equations with the massive gluon-quark splitting kernels for strange and charm quarks, the massless gluon-quark splitting kernels for up and down quarks, and the massless kernels for all other splitting parts. The SU(2)f flavor symmetry for two light quarks, ‘up’ and ‘down’, is assumed. Glück-Reya-Vogt(GRV) and Martin-RobertsStirling(MRS) sets are chosen to be the base structure functions at Q0 = 3 GeV 2. We evolve the sea structure functions from Q0 = 3 GeV 2 to Q2 = 50 GeV2 using the base structure function sets and DGLAP equations. Some (about 10%) enhancement is found in the strange quark distribution functions at low x(< 0.1) in leading order of the DGLAP equations compared to results direclty from those structure function sets at the the value of Q2 = 50 GeV2. We provide the value of κ and also show the behavior of κ(x) = 2s(x)/(ū(x) + d̄(x)) after the evolution of structure functions.