Effect of bound nucleon internal structure change on nuclear structure functions

Abstract

Effect of bound nucleon internal structure change on nuclear structure functions is investigated based on local quark-hadron duality. The bound nucleon structure functions calculated for charged-lepton and (anti)neutrino scattering are all enhanced in symmetric nuclear matter at large Bjorken-$x$ ($x\text{agt}0.85$) relative to those in a free nucleon. This implies that a part of the enhancement observed in the nuclear structure function $F_2$ (in the resonance region) at large Bjorken-$x$ (the EMC effect) is due to the effect of the bound nucleon internal structure change. However, the $x$ dependence for the charged-lepton and (anti)neutrino scattering is different. The former [latter] is enhanced [quenched] in the region $0.8\text{alt}x\text{alt}0.9$ [$0.7\text{alt}x\text{alt}0.85$] due to the difference of the contribution from axial vector form factor. Because of these differences charge symmetry breaking in parton distributions will be enhanced in nuclei.

Comments: 12 pages, 4 figures, to be published in PLB. Effect of Fermimotion is included. Accordingly, 4 figures as well as the text were modified