Internal {gamma} Decay and the Superallowed Branching Ratio for the {beta}{sup +} Emitter {sup 38}K{sup m}
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)
- Department of Physics, Queen's University, Kingston, Ontario K7L 3N6 (Canada)
- Department of Astronomy and Physics, St. Mary's University, Halifax, Nova Scotia B3H 3C3 (Canada)
The branching ratio for the superallowed {beta}{sup +} decay of {sup 38}K{sup m} was measured at TRIUMF's ISAC radioactive ion beam facility. The M3 internal transition between the isomer and the ground state of {sup 38}K{sup m} was observed with a branching ratio of 330(43) ppm. A search for the nonanalogue {beta}-decay branch to the first excited 0{sup +} state in {sup 38}Ar was also performed and yielded an upper limit of {<=}12 ppm at 90% C.L. These measurements lead to a revised superallowed branching ratio for {sup 38}K{sup m} of 99.967(4)%, and increase the {sup 38}K{sup m} ft value by its entire quoted uncertainty to ft=3052.1(10) s. Implications for tests of the nuclear-structure dependent corrections in superallowed {beta} decays and the extraction of the Cabibbo-Kobayashi-Maskawa matrix element V{sub ud} are discussed.
- OSTI ID:
- 21132419
- Journal Information:
- Physical Review Letters, Vol. 100, Issue 19; Other Information: DOI: 10.1103/PhysRevLett.100.192504; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
- Country of Publication:
- United States
- Language:
- English
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