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The parallel momentum distribution (PMD) of the residual nuclei of the 14O(p,pn)13O and 14O(p,2p)13N reactions at 100 and 200 MeV/nucleon in inverse kinematics is investigated with the framework of the distorted wave impulse approximation. The PMD sh ows an asymmetric shape characterized by a steep fall-off on the high momentum side and a long-ranged tail on the low momentum side. The former is found to be due to the phase volume effect reflecting the energy and momentum conservation, and the latter is to the momentum shift of the outgoing two nucleons inside an attractive potential caused by the residual nucleus. Dependence of these effects on the nucleon separation energy of the projectile and the incident energy is also discussed.
The breakup cross section (BUX) of 22C by 12C at 250 MeV/nucleon is evaluated by the continuum-discretized coupled-channels method incorporating the cluster-orbital shell model (COSM) wave functions. Contributions of the low-lying 0+_2 and 2+_1 reson ances predicted by COSM to the BUX are investigated. The 2+_1 resonance gives a narrow peak in the BUX, as in usual resonant reactions, whereas the 0+_2 resonant cross section has a peculiar shape due to the coupling to the nonresonant continuum, i.e., the Fano effect. By changing the scattering angle of 22C after the breakup, a variety of shapes of the 0+_2 resonant cross sections is obtained. Mechanism of the appearance of the sizable Fano effect in the breakup of 22C is discussed.
The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-bound nuclei at intermediate energies collisions. For large impact parameters, the Eikonal CDCC (E-CDCC) method was applied. The effects of Lorentz contra ction on the nuclear and Coulomb potentials have been investigated in details. Such effects tend to increase cross sections appreciably. We also show that, for loosely-bound nuclei, the contribution of the so-called close field is small and can be neglected.
177 - K. Ogata 2009
The dependence of breakup cross sections of 8B at 65 MeV/nucleon on the target mass number A_T is investigated by means of the continuum-discretized coupled-channels method (CDCC) with more reliable distorting potentials than those in the preceding s tudy. The A_T^(1/3) scaling law of the nuclear breakup cross section is found to be satisfied only in the middle A_T region of 40 < A_T < 150. The interference between nuclear and Coulomb breakup amplitudes vanishes in very forward angle scattering, independently of the target nucleus. The truncation of the relative energy between the p and 7Be fragments slightly reduces the contribution of nuclear breakup at very forward angles, while the angular region in which the first-order perturbation theory works well does not change essentially.
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