Important role of three-body repulsive force effect in nuclear reactions

Abstract

Abstract. The effect of three-body force (TBF) is studied in nucleus-nucleus elastic scattering on the basis of Brueckner theory for nucleon-nucleon (NN) effective interaction (complex G matrix) in the nuclear matter. A new G matrix called CEG07 proposed recently by the present authors includes the TBF effect and reproduces a realistic saturation curve in the nuclear matter, and is shown to well reproduce proton-nucleus elastic scattering. The microscopic optical potential for nucleus-nucleus system is obtained by folding the G matrix with nucleon density distributions in colliding nuclei. We first analyze the 16 O + 16 O elastic scattering at E/A = 70 MeV in detail. The observed cross sections are nicely reproduced up to the most backward scattering angles only when the TBF effect is included. The effects of the three-body attraction (TBA) and three-body repulsion (TBR) are also analyzed. The TBR contribution has an important role in nucleus-nucleus elastic scattering. The CEG07 G matrix is also tested in the elastic scattering of 16 O by the 12 C, 28 Si and 40 Ca targets at E/A = 93.9 MeV, and in the elastic scattering of 12 C by the 12 C target at E/A = 135 MeV with a great success. The decisive effect of the TBF is clearly seen also in those systems.

Deuteron–proton breakup at medium energies

“…4 P ZZ . An analysis relying on the integrated rates allows one to extract ReT 20 independently from all other analyzing power components, thus free of uncertainties due to possible correlations between them in case a fit of expression (23) or (25) to the distribution of rates is used. Such an integral method is, however, very sensitive to systematic effects related to incomplete integration over φ, due to losses of acceptance or variation of efficiency, and to uncertainty of normalization (κ = 1).…”

“…The 3NF is supposed to be one of the key issues not only in nuclear physics but also in nuclear astrophysics, relevant to high-density nuclear matter in neutron stars and supernova explosions. The folding model studies of the nucleon-nucleus and nucleus-nucleus elastic scattering, with the G-matrix including attractive and repulsive 3NF, have been performed, showing the importance of these contributions for a correct description of the differential cross section [25]. Other authors have considered 3NF an explanation of the anomaly in the neutron drip-line present for oxygen isotopes [26], or have studied the influence of 3NFs on neutron super-fluidity in neutron-rich matter and neutron stars [27,28].…”