High x Structure Function of the Virtually Free Neutron

Understand

The pole extrapolation method is applied to the semi-inclusive inelastic electron scattering off the deuteron with tagged spectator protons to extract the high-x structure function of the neutron.

• This approach is based on the extrapolation of the measured cross sections at different momenta of the spectator proton to the non-physical pole of the bound neutron in the deuteron.
• The advantage of the method is in the possibility of suppression of the nuclear effects in a maximally model-independent way.
• The neutron structure functions obtained in this way demonstrate a surprising x dependence at $x\ge 0.6$ and $1.6 \leq Q^2 \leq 3.38$ GeV$^2$, indicating a possible rise of the neutron to proton structure function ratio.