(Received April 17, 2000)
The L = 0 phase shift of nucleon-trinucleon elastic scattering for total spin and isospin ST = 00 state is obtained by extending the calculation for a four-boson system to the four-nucleon case. A spin-dependent rank-one separable potential of the Yamaguchi type is introduced for the two-nucleon interaction instead of a spin-independent potential. In this paper, to estimate the contributions from the spin and isospin variables separately, the partial wave components of the angular momentum decomposition for the 3+1-subamplitude are restricted to s-waves only. The calculated phase shift reflects the existence of two resonances of the standard Breit-Wigner type; the phase shift passes through π/2 and 3π/2 successively, which are located on a portion of the phase shift curve that is nearly linear. These two resonances are extremely sharp and form a pair of very high peaks, completely isolated but very close to each other in the curve of the partial cross section. The calculated resonance energies are 0.1704 MeV and 0.1741 MeV, respectively. As for the calculated level width, a discrepancy was found between the actual width of each peak of the partial cross section and the width that was obtained in conformity with the resonance formula of Breit-Wigner. For the first resonance, the values are 0.0105 MeV and 0.00604 MeV, and for the second one they are 0.0077 MeV and 0.0056 MeV.
URL : http://ptp.ipap.jp/link?PTP/104/981/
DOI : 10.1143/PTP.104.981