Experimental Results on Scaling and the Neutron to Proton Cross Section Ratio in Deep Inelastic Electron Scattering

A review of present knowledge about the scaling of the neutron and proton structure functions and about the neutron to proton cross section ratio is presented, Emphasis is placed on the results of a recent electron scattering experiment at SLAC from which neutron cross sections were extracted from deuterium data using an impulse approximation, The discovery of scaling' * in deep inelastic electron proton scattering resulted in the formulation of a number of theoretical models explaining the experimental data, Additional measurements2-' have established that the neutron exhibits scaling, but that the neutron cross sections are different from the proton cross sections, The study of the comparison of neutron and proton cross sections provide valuable tests of those nucleon structure models, In this presentation, we will review some of the experimental evidence for scaling in deep inelastic electron scattering. Emphasis will be placed on the results of a recent electron scattering experiment at S&X2 in which e-p and e-n cross sections were compared. A detailed discussion of the apparatus used in these electron scattering experiments can be found in Refs. 1-6, Briefly, an electron beam of energy E is incident on a liquid hydrogen or liquid deuterium target, Scattered electrons are detected by a magnetic spectrometer. The cross section d’a/dII dE’ is measured for several scattering angles 0 and various initial and final electron energies E and E'. In the one photon exchange approximation, the cross section is represented by two structure functions WI and W2, *Present address: Stanford Linear Accelerator Center **Work supported in part by the U.S. Atomic Energy Commission under Contract BAT(ll-1) 3069 + Present address: Laboratory of Nuclear Studies, Cornell University (Presented at the 1973 Meeting of the Division of Particles and Fields of the APS, Berkeley, California, August 13-17, 1973) i