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

Abstract

The importance of Δ(1232) isobar degrees of freedom is investigated for the transverse (e, e′) response of 3He 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 RT are presented up to q = 700 MeV/c, whereas for higher q only some preliminary results for the LIT of RT are discussed. In the quasi-elastic peak region Δ-IC enhance RT by about 5% and tend to cancel three-nucleon force effects. One observes an excellent agreement with experimental RT 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.