On the Nucleon-Nucleon Scattering Phase Shifts and the High Energy Nucleons Elastically Scattered from Light Nuclei

Abstract

The polarizations and triple scattering parameters of the nucleons elastically scattered from light nuclei are explained with the optical model potential by the use of the nucleon-nucleon scattering phase shifts. The set of the two-body scattering phase shifts meson-theoretically derived gives a small magnitude of the parameter of optical model potential V SR. The small value of V iW is mainly caused by the large positive 3Po state phase shift of the two-body scattering. The small value of V SN gives a small polarization and a small absolute value of the triple scattering parameter for the nucleon scattered from the potential. Furthermore the value of i:;i ChjjJ.c) 2 calculated by the use of the meson-theoretical phase shifts is smaller than the ones based on the Gammel-Thaler and Signell-Marshak phase shifts. This difference is mainly due to the difference of 3PO state phase shifts in the two-body scattering. polarizations of the high energy nucleons elastically scattered from light nuclei, using the impulse approximation with the nucleon-nucleon scattering amplitude, for the impulse approximation is equivalent to the use of the optical model potential in the first Born approximation which may be justified for the small angle scatter­ ing from light nuclei. 4 ),5) The ordinary procedure is that, given several alternative sets of the nucleon-nucleon scattering phase shifts, the optical model potentials cor­ responding to the sets of the phase shifts are derived, and then the differential cross Sections and polarizations of the nucleons scattered in small angles are calcu­ lated. The comparison of the results with the observed differential cross sections and polarizations may distinguish the various sets of the nuclear phase shifts re­ jecting some of them. ,_ The best way of studying the nucleon-nucleon interactions by the use of these optical model potential is to investigate the polarizations and triple scattering pa­ rameters of the nucleons elastically scattered from light nuclei, because when one calculates the polarizations and triple scattering parameters of these nucleons through the optical model potentials, the final results are independent of the detailed structure of the target nucleus and to a certain extent free from the limitation of the Born approximation. That is, the expressions for the polarization and triple Bcattering parameter do not contain the nuclear form factors~ i.e. the Fourier trans