Improved transverse (e,e') response function of 3He at intermediate momentum transfers

TL;DR

This study improves the theoretical calculation of the transverse electron scattering response function of helium-3 at intermediate momentum transfers by using a specialized reference frame and relativistic corrections, achieving better agreement with experimental data.

Contribution

The paper introduces a novel approach using the ANB frame and relativistic current corrections to enhance the accuracy of response function predictions for helium-3.

Findings

Response peak position aligns well with experiment.

Peak height matches at 500 MeV/c but exceeds at 700 MeV/c.

Use of ANB frame shifts peak to lower energy and increases peak height.

Abstract

The transverse electron scattering response function of 3He is studied in the quasi-elastic peak region for momentum transfers between 500 and 700 MeV/c. A conventional description of the process leads to results at a substantial variation with experiment. To improve the results, the present calculation is done in a reference frame (the ANB or Active Nucleon Breit frame) which diminishes the influence of relativistic effects on nuclear states. The laboratory frame response function is then obtained via a kinematics transformation. In addition, a one-body nuclear current operator is employed that includes all leading order relativistic corrections. Multipoles of this operator are listed. It is shown that the use of the ANB frame leads to a sizable shift of the quasi-elastic peak to lower energy and, contrary to the relativistic current, also to an increase of the peak height. The additionally considered meson exchange current contribution is quite small in the peak region. In comparison with experiment one finds an excellent agreement of the peak positions. The peak height agrees well with experiment for the lowest considered momentum transfer (500 MeV/c), but tends to be too high for higher momentum transfer (10% at 700 MeV/c).