  The transverse response function R_T(q,omega) for 3He is calculated using the
configuration space BonnA nucleon-nucleon potential, the Tucson-Melbourne
three-body force, and the Coulomb potential. Final states are completely taken
into account via the Lorentz integral transform technique. Non-relativistic
one-body currents plus two-body pi- and rho-meson exchange currents as well as
the Siegert operator are included. The response R_T is calculated for q=174,
250, 400, and 500 MeV/c and in the threshold region at q=174, 324, and 487
MeV/c. Strong MEC effects are found in low- and high-energy tails, but due to
MEC there are also moderate enhancements of the quasi-elastic peak (6%-10%).
The calculation is performed both directly and via transformation of electric
multipoles to a form that involves the charge operator. The contribution of the
latter operator is suppressed in and below the quasielastic peak while at
higher energies the charge operator represents almost the whole MEC
contribution at the lowest q value. The effect of the Coulomb force in the
final state interaction is investigated for the threshold region at q=174
MeV/c. Its neglect enhances R_T by more than 10% in the range up to 2 MeV above
threshold. In comparison to experimental data one finds relatively good
agreement at q=250 and 400 MeV/c, while at q=500 MeV/c, presumably due to
relativistic effects, the theoretical quasi-elastic peak position is shifted to
somewhat higher energies. The strong MEC contributions in the threshold region
are nicely confirmed by data at q=324 and 487 MeV/c.
