The 3He transverse electron scattering response function R_T(q,omega) is calculated in the quasi-elastic peak region and beyond for momentum transfers q = 500, 600 and 700 MeV/c. Distinct from our previous work for these kinematics where we included
meson exchange currents and relativistic corrections we now additionally include Delta isobar currents (Delta-IC). The Delta-IC contribution increases the quasi-elastic peak height by about 5% and leads to an excellent agreement with experimental data in the whole peak region. In addition it is shown that effects due to the three-nucleon force largely cancel those due to the Delta-IC in the peak region. Finally, we have found that Delta-IC are important for three-body break-up reactions in the so-called dip region. This could explain why in a previous study of such a reaction, where Delta degrees of freedom were not included, no agreement between experimental and theoretical results could be obtained.
The transverse electron scattering response function of 3He was recently studied by us in the quasi-elastic peak region for momentum transfers q between 500 and 700 MeV/c. Those results, obtained using the Active Nucleon Breit frame (ANB), are here s
upplemented by calculations in the laboratory, Breit and ANB frames using the two-fragment model discussed in our earlier work on the frame dependence of the the longitudinal response function R_L(q,omega). We find relatively frame independent results and good agreement with experiment especially for the lower momentum transfers. This agreement occurs when we neglect an omega-dependent piece of the one-body current relativistic correction. An inclusion of this term leads however to a rather pronounced frame dependence at q=700 MeV/c. A discussion of this term is given here. This report also includes a correction to our previous ANB results for R_T(q,omega).
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 exper
iment. 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).
