Threshold electrodisintegration in the A=3 system

Inclusive inelastic electron scattering cross sections for H3 and He3 were measured for excitation energies below 18 MeV. Longitudinal and transverse response functions were determined from these cross sections for six values of the three-momentum transfer q in the range 0.88 <q<2.87 fm-1. A previously observed C0 multipole enhancement near threshold in the two-body channel for He3 is confirmed but is not observed for H3. The experimental data are found to be in good agreement with two recent calculations of the longitudinal and transverse response functions. The first uses variational ground-state wave functions and the orthogonal correlated states method to describe the two- and three-body breakup channels. The second uses bound and continuum Faddeev wave functions obtained for a simple central potential. Agreement with the data is good for the first model and better for the second. The inclusion of final-state interactions (FSI) in the Faddeev continuum is found to be very important in these threshold breakup kinematics; in many cases inclusion of FSI changes the response functions by factors of two or three giving excellent agreement with the data. The transverse response functions are well reproduced, even though neither model includes meson exchange currents. Ratios of the response functions for the two nuclei are also well described.