Δ Isobar Degrees of Freedom in the 3 He Transverse Electron Scattering Response Function

The importance of Δ (1232) isobar degrees of freedom is investigated for the transverse ( e , e ′) response of 3 He in the quasi-elastic peak region and beyond (considered momentum transfer range: 500 ≤ q ≤ 1,000 MeV/c). Besides Δ isobar currents ( Δ -IC) meson exchange currents and relativistic corrections to the nucleonic one-body current are included. The calculation is carried out by using the Lorentz integral transform (LIT) method. Results for the transverse response function R T are presented up to q = 700 MeV/c, whereas for higher q only some preliminary results for the LIT of R T are discussed. In the quasi-elastic peak region Δ -IC enhance R T by about 5% and tend to cancel three-nucleon force effects. One observes an excellent agreement with experimental R T results. Particularly strong Δ -IC contributions are found for transitions into the final state with isospin T = 3/2, which is only reachable in three-body break-up reactions.