Extracting the number of short-range correlated nucleon pairs from inclusive electron scattering data

The extraction of the relative abundances of short-range correlated (SRC) nucleon pairs from inclusive electron scattering is studied using the generalized contact formalism (GCF) with several nuclear interaction models. GCF calculations can reproduce the observed scaling of the cross-section ratios for nuclei relative to deuterium at high x(B) and large Q(2), a(2) = (sigma(A)/A)/(sigma(d)/2). In the nonrelativistic instant-form formulation, the calculation is very sensitive to the model parameters and only reproduces the data using parameters that are inconsistent with ab initio many-body calculations. Using a light-cone GCF formulation significantly decreases this sensitivity and improves the agreement with ab initio calculations. The ratio of similar mass isotopes, such as Ca-40 and Ca-48, should be sensitive to the nuclear asymmetry dependence of SRCs, but is found to also be sensitive to low-energy nuclear structure. Thus the empirical association of SRC pair abundances with the measured a(2) values is only accurate to about 20%. Improving this will require cross-section calculations that reproduce the data while properly accounting for both nuclear structure and relativistic effects.

Automated summary

The study shows that the extraction of the relative abundances of short-range correlated nucleon pairs using the generalized contact formalism (GCF) is sensitive to model parameters, with the light-cone GCF formulation significantly reducing this sensitivity and improving consistency with ab initio calculations. The ratio of similar mass isotopes is found to be sensitive to nuclear asymmetry dependence of SRCs and low-energy nuclear structure, suggesting the need for cross-section calculations that properly account for both nuclear structure and relativistic effects to improve accuracy.