Isoscalar spin response functions in the quasielastic scattering region

Abstract

The role of particle-hole correlations in isoscalar spin response functions in the quasielastic scattering region is examined within the continuum RPA. Both spin-longitudinal and spin-transverse response functions are appreciably modified from the free response function without correlations, due to the repulsive central force and the exchange term of the tensor force in the particle-hole interaction. The latter force also induces an appreciable difference between the two isoscalar spin response functions. It is shown that the ground-state correlation (the backward-going contribution) due to the tensor force is important in the large momentum transfer region and is not weakened, even at large energy transfer. The experimental ratio between the two spin response functions at q=1.75fm −1 observed in (p, p') reactions is not largely modified around the quasielastic scattering peak by including particle-hole correlations in the spin-isoscalar mode. On the other hand, it is somewhat reduced in the large energy transfer region above the quasielastic scattering peak.