Unpolarized transverse-momentum- dependent sea quark asymmetries of light nuclei in nonperturbative QCD

We investigate the transverse-momentum dependence of sea quark asymmetries in helium and deuteron nuclei. Accordingly, we calculate the nuclear sea quark distributions, in the first step, based on the modified chiral quark exchange formalism at the low Q(2) scale (Q(2) = 0.35 GeV2) in the nonperturbative region of quantum chromodynamics. In this formalism, the sea quark distributions are not symmetric because of chiral symmetry breaking. In the next step, we compute the transverse-momentum dependence of sea quark distributions using the covariant parton model, in which the unpolarized transverse-momentum-dependent (TMD) quark distribution functions are related to corresponding integrated ones. Finally, we obtain TMD quarkantiquark asymmetry of the strange sea for He-3 and deuteron, and also (d(-) - u(-)) asymmetry for He-3. To study the European Muon Collaboration (EMC) effect in the He-3 nucleus, we determine the ratio of the TMD strange sea asymmetries of He-3 and deuteron.