Spin dependent parton distributions in a bound nucleon

Abstract

The determination of the spin distribution functions for the neutron requires an understanding of the changes induced by a nuclear medium. We present the first estimates of the changes induced in the spin-dependent, valence parton distributions of the proton and neutron bound in 3 He and 6 Li. For 3 He the result is quite reassuring, in that the off-shell correction to g 1 n is very small. On the other hand, in 6 Li the corrections to the spin distributions in the bound proton are sufficiently large that they should be taken into account if one aims for a precision of better than 10%. We provide a simple parametrization of the off-shell changes in the valence spin distributions of 3 He and 6 Li, which can be used with any conventional estimate of nuclear binding and Fermi motion corrections.