Threshold 3He and 3H Transverse Electron Scattering Response Functions

Abstract

The threshold transverse response functions R T (q, ω) for 3 He and 3 H are calculated using the AV18 nucleon-nucleon potential, the UrbanaIX three-body force, and the Coulomb potential. Final states are completely taken into account via the Lorentz integral transform technique. Consistent two-body π-and ρ-meson exchange currents as deduced using the Arenhövel-Schwamb technique are included. The convergence of the method is shown and a comparison of the corresponding MEC contribution is made to that of a consistent MEC for the meson theoretical r-space BonnA potential. The response R T is calculated in the threshold region at q=174, 324, and 487 MeV/c and compared with available data. The strong MEC contributions in the threshold region are nicely confirmed by the data at q=324 and 487 MeV/c although some differences between theoretical and experimental results remain. A comparison is also made with other calculations, where the same theoretical input is used. The agreement is generally rather good, but leaves also some space for further improvement.

Electromagnetic reactions on light nuclei

“…In Figure 16 [192] obtained with the LIT method point to the importance of MEC. The curve including MEC (red solid) leads to a considerably improved agreement with experimental data with respect to the IA calculation (blue dashed curve).…”

“…[191] employing the LIT method. Conventional 3N forces were found, e.g., to reduce R L in the quasi-elastic peak by 5-10% in the momentum transfer regime between 174 MeV † Note that the authors use a slightly different power counting, in particular they count Q/m as [192] in comparison to those by by Viviani et al [186] and by Golak et al [168], where the same Hamiltonian (AV18+UIX) has been used, but slightly different current operators, including MEC, have been implemented (see also text). and about 400 MeV.…”

Transverse electron scattering response function ofHe3withΔ-isobar degrees of freedom

“…In order to solve Eqs. (7), (11) and (12) for the ground state and Lorentz vectors we expand the bound and Lorentz states on a complete antisymmetric basis. The reason for antisymmetrizing NN∆ states is that they couple to purely antisymmetric nucleonic states through symmetric operators.…”

“…Explicit expressions for the multipoles of the one-body current (containing relativistic corrections) are given in [18]. The multipoles for the π-and ρ-MEC are found in [6] with modifications due to the implementation of consistent MECs for the AV18 potential listed in [7]. Finally the multipoles required here for the one-body currents relating to the ∆ are listed in Appendix D. With these multipoles one can then decompose the LIT of the response function according to its multipole content as…”

Manifestation of one- and two-body currents in longitudinal and transverse response functions of the 12C nucleus at q = 300 MeV/c

“…So far, the response function calculations, which are in fairly good agreement with the experiment, have been performed only for the nuclei with A ≤ 4 (e.g., see refs. [1,2]).…”