The effect of quark exchange in A=3 mirror nuclei and neutron/proton structure functions ratio

By using the quark-exchange formalism, realistic Faddeev wave functions and Fermi motion effect, we investigate deep inelastic electron scattering from A=3 mirror nuclei in the deep-valence region. The initial valence quarks in put are taken from the GRV's next-to-leading order calculations on $F_2^p(x,Q^2)$ which give very good fit to the available data in the $(x,Q^2)$-plane. It is shown that the free neutron to proton structure functions ratio can be extracted from corresponding EMC ratios for $^3He$ and $^3H$ mirror nuclei by using self-consistent iteration procedure and the results are in good agreement with other theoretical models as well as present available experimental data, especially the one expected form the proposed 11 GeV Jefferson Laboratory.