Study of the p + ^3H and n + ^3He Final-State Interactions in the Reactions ^7Li(p,ɑ) and D(^3He,p)

[摘要] The ɑ-particle energy spectra from the bombardment of ⁷Liwith 9.1-MeV protons have been obtained at 2.5° ≤ ϴ_ɑ ≤ 120°. Thehigh-energy ends of the spectra are interpreted as due to the ¹Sp + ³H final-state interaction through the first excited state of ⁴Heat 20.06 MeV. The factored-wave-function method is used to deducethe resonance parameters of this state. Consistency in theuse of this method is obtained by a PWBA calculation based on thetriton-transfer mechanism to account for the forward-peaking inthe angular distribution. Coincidence measurements between a-particlesand the other charged particles give additional evidencefor the 0⁺ assignment to the state, and indicate that the a + ³H anda + H final-state interactions are important as the ⁴He excitationenergy gets higher. To reduce the effects of these final-state interactions,the reaction D(³He, p), at a ³He bombarding energy of16.5 MeV, has been investigated. The protons emitted from thereaction have been measured at ϴ_p = 30° in coincidence with theother charged particles. Angular correlations have been obtainedfor 6.6 MeV ≤ E_p ≤ 8.6 MeV, and compared with a modified Bornapproximation calculation based on the stripping of ³He. Theangle-energy correlation and the p - ³H to p - ³He branching ratiocan be reproduced, if Meyerhof's p + ³H phase shifts and Bransden'sn + ³He phase shifts are used to describe their respective interactionsin the final states. In agreement with the reported 0^- stateat 21.2 MeV, the p-wave final-state interactions are found to beimportant in this energy range.

[发布机构] University:California Institute of Technology;Department:Physics, Mathematics and Astronomy

[关键词] Physics