|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1996 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1995 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1994 : ¥1,400,000 (Direct Cost : ¥1,400,000)
The purpose of relativistic models for nuclei is to analyze high energy phenomena and to investigate the relationship between QCD and conventional nonrelativistic nuclear models. Walecka has proposed a relativistic model which assumes nuclei to be a relativistic system composed of nucleons and mesons. This model seems to be natural, because the nonrelativistic nuclear models empoly nuclear interactions which are assumed to come from meson exchanges between nucleons. Indeed, it has been shown that Walecka model works very well to explain low and intermediate energy phenomena. On the other hand, however, this model provides a serious problem, since this model is not reduced to conventional nonrelativistic models at low energy limit. Relativistic effects are shown to be important even for reproducing the nucleon density and binding energy.
Our purpose is to find nuclear phenomena theoretically which are peculiar to the relativistic model and show clearly the difference between the relativistic and nonrelativistic models. We have shown that the Coulomb sum rule in the relativistic model is very different from the one in nonrelativistic models. In nonrelativistic models, the Coulomb sum rule value for electron scattering should be equal model-independently to the proton number of the system above the momentum transfer, 500 MeV.On the other hand, the relativistic model predicts the Coulomb sum rule value to be about a half of the proton number around the momentum transfer, 1GeV.This reduction is due to the nucleon antinucleon correlations which is peculiar to the relativistic model. Experimentally the Coulomb sum rule value is not clear yet, since there are disagreements between the data from MIT and Sacley. If the value is flxed experimentally, the relationship between the relativistic and nonrelativistic models is expected to be apparent.