Deep inelastic scattering fromA=3nuclei and the neutron structure function

Abstract

We present a comprehensive analysis of deep inelastic scattering from ${}^{3}\mathrm{He}$ and ${}^{3}\mathrm{H},$ focusing in particular on the extraction of the free neutron structure function ${F}_{2}^{n}.$ Nuclear corrections are shown to cancel to within 1--2% for the isospin-weighted ratio of ${}^{3}\mathrm{He}$ to ${}^{3}\mathrm{H}$ structure functions, which leads to more than an order of magnitude improvement in the current uncertainty in the neutron to proton ratio ${F}_{2}^{n}{/F}_{2}^{p}$ at large x. Theoretical uncertainties originating from the nuclear wave function, including possible non-nucleonic components, are evaluated. Measurements of the ${}^{3}\mathrm{He}$ and ${}^{3}\mathrm{H}$ structure functions will, in addition, determine the magnitude of the EMC effect in all $A<~3$ nuclei.