MECHANISM OF THE FORWARD-ANGLE (D,PN) REACTION AT INTERMEDIATE ENERGIES

The elastic breakup of the deuteron has been measured in a kinematical condition of theta(p) = theta(n)= 0 degrees at E-d = 140 MeV and 270 MeV on seven targets ranging from Z = 6 to 82. A double-peaked structu re with its minimum at E-p similar or equal to E-n is observed for all the measured triple-differential cross sections; which indicates a la rge contribution from Coulomb breakup. While a symmetric shape is expe cted for an E1 transition, the observed proton-energy distribution is asymmetric, showing considerable dependence on both the target and the incident energy. These data and previous data at 56 MeV have been ana lyzed using the post-form of the distorted-wave Born approximation (DW BA) theory. Although the calculations account reasonably well for the asymmetric shape, by including the nuclear potential, they consistentl y overestimate the magnitudes of the cross sections over the whole mea sured region. Limitations of the post-form DWBA are discussed. [S0556- 2813(98)03910-7].