Reaction 13C(n,p)13B at 65 MeV.

Abstract

The reaction {sup 13}C({ital n},{ital p}){sup 13}B has been studied at {ital E}{sub {ital n}}=65 MeV. Cross sections were measured for transitions to the ground state and excited states of {sup 13}B from 0{degree} to 40{degree}. The 0{degree} cross section to the ground state gives a value of 179{plus_minus}20 MeVfm{sup 3} for {ital V}{sub {sigma}{tau}}{sup {ital c}}, the spin-isospin central part of the volume integral of the effective {ital N}-{ital N} interaction. A theoretical calculation, 181.3 MeVfm{sup 3}, is in good agreement with this result. Distorted-wave impulse-approximation calculations are compared with the experimental angular distributions. Good agreement is obtained for the dominant Gamow-Teller transition to the ground state of {sup 13}B. The evidence obtained here, together with results from the analogous reaction {sup 13}C({pi}{sup {minus}},{gamma}){sup 13}B, suggests that transitions to states at 6.5 and 7.6 MeV are spin dipole in character and that the broad resonance at 10.2 MeV is chiefly the analog of the giant {ital E}1 resonance in {sup 13}C. {copyright} {ital 1996 The American Physical Society.}