The 16O(α, p)19F reaction at Eα = 40 MeV

doi:10.1016/0375-9474(76)90306-7

Nuclear Physics A

Volume 273, Issue 1, 23 November 1976, Pages 172-188

https://doi.org/10.1016/0375-9474(76)90306-7 Get rights and content

Abstract

The ¹⁶O(α, p)¹⁹F reaction has been studied at E_α = 40 MeV. In this reaction high-spin states at high excitation energy are selectively excited. A study of positive parity states ranging from $J^{π} = 12^{+}$ to $132^{+}$ shows that the reaction can be described in terms of a direct transfer of a three-nucleon cluster with internal quantum numbers l = 0 and $s = 12$ . An analysis in terms of a zero-range DWBA calculation accounts rather well for the shape of the angular distributions. The relative spectroscopic factors S for the transitions to the $J^{π} = 12^{+}$ , $32^{+}$ , $52^{+}$ , $72^{+}$ and $92^{+}$ states have been compared with the intensity of the (λ, μ) = (6, 0) component in the SU(3) wave functions and are found to be in excellent agreement with calculated values. For the assumed $J^{π} = 112^{+}$ state at E_x = 9.90 MeV and the $J^{π} = 132^{+}$ states at E_x = 4.65 and 10.42 MeV the S-values are about three times larger than calculated. This might be due to small (sd)(fp)² admixtures in the wave functions for these states. The analysis of the transitions to the negative parity states indicates that the shape of their angular distributions is sensitive to whether the transferred three-nucleon cluster originates from a p(sd)² or a (sd)²(fp) coupling. Two negative parity states at E_x = 8.9 and 12.8 MeV are rather strongly populated. They could be the lower spin members of the weak-coupling doublets arising from the coupling of a p_$12$. hole to the ²⁰Ne J^π = 6⁺ and 8⁺ states, respectively. No evidence is found for the excitation of the high-spin members. This is in agreement with the cluster model of Buck et al. which takes into account the spin-orbit potential of the triton cluster.

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Nuclear Physics A

Abstract

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A DWBA analysis of heavy-ion induced three-nucleon transfer reactions on <sup>15</sup>N, <sup>16</sup>O AND <sup>18</sup>O