Microscopic theory of the 4He system with multichannel resonating-group method.

Abstract

The ground and even-parity excited states and the scattering problem of the /sup 4/He system are examined within the framework of the (2N+2N) and (1N+3N) cluster-coupling model with the specific distortion effect of the deuteron cluster taken into consideration. Calculations are performed by a multichannel resonating-group method using an effective nucleon-nucleon (NN) potential similar to that adopted in p+..cap alpha.., d+..cap alpha.., /sup 3/H+..cap alpha.. (or /sup 3/He+..cap alpha..), and ..cap alpha..+..cap alpha.. systems. The results show that, because of the high compressibility of the deuteron cluster and the similarity in threshold energies for the 2N+2N and 1N+3N configurations, both the distortion effect and the channel-coupling effect are important in this system. When the 1N+3N configuration is included in the calculation, the deuteron-distortion effect turns out to be significantly weakened, owing to the fact that the 1N+3N configuration is energetically the most favored one. In addition, it is shown that such a specific distortion effect is quite small in the channel spin S-italic = 2 state of d+d scattering. With the full calculation including the distortion effect, it is found possible to reproduce well the energies of the ground state and the first-excited 0/sup +/ state; the differential cross sectionsmore » for d+d, p+t, and n+h elastic scattering; the polarizations for p+t and n+h scattering; and the cross sections for /sup 1/H(t,n)/sup 3/He and /sup 3/H(p,d)/sup 2/H reactions.« less