The giant dipole resonances in 11C and 15O observed with the reactions 10B(p, γ) 11C and 14N(p, γ) 15O

Abstract

The giant dipole resonances in 11C and 15O have been studied with the capture reactions su10B(p, γ 0) 11C ( E p = 2.6-17.0 MeV) and 14N(p, γ 0) 15O ( E p = 2.2–19.0 MeV). Some similarity is observed between the giant dipole resonances in 11C and 12C and between those in 15O and 16O. The average (γ, p 0) cross sections for 11C and 15O are smaller by a factor of about 3 than those for 12C and 16O. However, the dipole strength is more spread out in 11C and 15O than in 12C and 16O. A comparison of results from 15N(γ, p 0) 14 14C and 15O(γ, p 0) 14N suggests the contribution of T = 3 2 states in the former reaction but not in the latter. The yields of the reactions 10 B( p, γ 1) 11 C∗ and 11 N( p, γ 1+γ 2) 15 O∗ are relatively weak and only estim their upper limits are obtained. For the sharp, low-lying resonances at E p = 2.35 and 2.48 MeV in 11N(p, γ 0) 15O previous assignments of 5 2 − and 3 2 − are confirmed. For the reson E p = 4.20 MeV 3 2 + is obtained.