  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).

Nuclear Theory