Comparison of the β-α Angular Correlations in the Beta Decays of Li⁸ and B⁸

Citation

Nordberg, Martin Emery, Jr (1961) Comparison of the β-α Angular Correlations in the Beta Decays of Li⁸ and B⁸. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/00je-ft97. https://resolver.caltech.edu/CaltechTHESIS:07152025-213640159

Abstract

This thesis describes a comparison of the β-α angular correlations of the beta decays of Li⁸ and B⁸ to the 2.90-Mev α-unstable state of Be⁸. The data are fitted to the angular correlation function in the laboratory system, W(ϴ_βα) = 1 + A cos ϴ_βα + B cos ²ϴ_βα, where A and B are independently determined for each decay from measurements at ϴ_βα = 0°, 90°, and 180°. The coefficient, A, is due to the recoil of Be^8* and has the same sign for both beta decays. The coefficient, B, arises from the interference of forbidden vector matrix elements with the allowed axial vector matrix element and changes sign in the two decays. The correlation for the Li⁸ decay is measured with average total β-energies of W_β ≃ 5, 8, and 11 Mev. Both A and B are approximately linear in the energy. The correlation for the B⁸ decay is measured only with average total β-energy of W_β ≃ 11 Mev. From the data with W_β ≃ 11 Mev, the difference of the coefficients, B(Li⁸) - B(B⁸), is equal to (0.0069 ± 0.0011)W_β. This result is compared with theoretical predictions based on the older Fermi and the newer Conserved Vector Current theories of beta decay. The experiment agrees with the prediction of the latter theory.

Thesis Files