Nuclear Interaction of Core Region

Abstract

In the former half of the paper, the singlet S phase shift 1J0 is calculated by assuming a nuclear potential with a soft core of the Yukawa shape, the Gaussian shape, or the modi­ fied Gaussian shape exp {- (ta) 4} surrounded by an attractive well with the one-pion­ exchange tail. It is shown that the short-tailed soft core as the Gaussian or the modified­ Gaussian shape can explain the behavior of 1J0 up to 1 GeV while the long-tailed core such as the Yukawa shape with the range >liM can not reproduce 1o 0 even in the energy region 0,..___200 MeV. It is argued that the explanation of the origin of the soft core in terms of a vector-meson-exchange is rather unprobable. The effective radius of the soft core is found to be 0.4'-'0.5/ ,u and the effective height a few Ge V. In the latter half of the paper, it is pointed out that the nuclear interaction may have ·a different nature outside and inside the effective core radius, by investigating the energy dependence of the absorption coefficient versus the impact parameter. The strong repulsion at low energies and the strong absorption at tens Ge V, which are characteristic to the inner part, could be regarded as a manifestation of degrees of freedom inherent in the core region. Importance of the nucleon-nucleon polarization measurement in: the GeV energy region as well as the measurement of the four momentum transfer in the cosmic ray nuclear interactions are discussed in order to go one step further in clarifying the core region interaction. A hypothetical interpretation on the substantial carrier of the degrees of free­ dom is proposed based on an analogy with nucleus that the carrier is a many-body-system of ur-fermions. The core is interpreted as the exchange repulsion due to the antisymmetriza­ tion among the ur-fermions.