Nuclear Effects in the F3 Structure Function

Experiments on deep-inelastic scattering (DIS) of charged leptons and neutrino remains an important source of information about the nucleon as well as about the nuclear structure. DIS experiments with neutrino beams 1,2 has reached now an accuracy comparable to that of experiments with charged leptons. Note in this respect that because of statistics reasons neutrino data are collected for heavy nuclei like iron . Nuclear effects have been extensively discussed for the spin independent structure functions (SF) F1,2 as well as for the spin SF g1,2 which are measured in the charged lepton DIS (for a recent reviews of experimental situation and theoretical approaches to nuclear effects in DIS see refs.), however untill now only a little attention was payed to nuclear effects in neutrino DIS. It is usually assumed in analysing neutrino data that nuclear corrections are the same as in charged lepton DIS. At large Q this assumption can be motivated by the parton model where the charged lepton and neutrino SF are expressed in terms of universal parton distributions. However the similarity between the charge lepton and neutrino F2 fails at small x where they are different in the strange and charm quarks content as well as when one studies effects due to finite Q. In this respect the situation is even more uncertain with the SF F3, which does not have its analog in the charged lepton DIS. In the present contribution we report on the results of our studies of nuclear effects in the SF F3 within an approach applicable at finite Q . More detailed discussion on this matter can be found in ref.. Nuclear effects in DIS are usually discussed within the context of the impulse approximation for the nucleons, where the nuclear Compton scattering amplitude is approximated by the uncoherent sum of the scattering amplitudes from bound nucleons neglecting final state interactions. An argument to support this approximation comes from the analysis of characteristic spacetime scales involved in deep-inelastic scattering. In the laboratory frame a characteristic time for DIS is 1/Mx, where M is the nucleon mass (see, e.g., ref.). For x > 0.2 this time is smaller than the typical average distance between bound nucleons in the nucleus and the scattering proceeds uncoherently.