[Triumf-seminars] TRIUMF Nuclear Physics Seminar today at 15:30

[TRIUMF Seminars]

Date/Time: Mon 2015-09-14 at 15:30

Location:  Auditorium          

Speaker:   Gordon Ball (TRIUMF)

Title:     Superallowed Fermi Beta Decay Studies at ISAC:  Testing CVC and CKM Unitarity

Abstract: Precision measurements of the ft values for superallowed Fermi beta decays between isobaric analogue states provide demanding tests of the electroweak Standard Model, including the most precise test of the Conserved Vector Current (CVC) hypothesis, the most stringent limits on maximally parity violating weak scalar currents and, in combination with muon decay, the most precise determination of the up-down (Vud) element of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix. At TRIUMF, world-leading capabilities have been developed at the ISAC facility for measuring all three of the experimental quantities required to determine superallowed ft values: high-precision beta decay Q-value determinations are made through mass measurements for the parent and daughter nuclei with the TITAN Penning trap facility, superallowed half-life measurements are performed through both beta counting with the 4pi gas proportional counter and fast tape transport system at the ISAC-I general purpose station (GPS) and through gamma counting with the 8pi gamma-ray spectrometer, while superallowed beta decay branching ratios are measured with the 8pi spectrometer. This suite of advanced experimental facilities at ISAC has enabled a number of major advances in high-precision superallowed Fermi beta decay studies over the past 15 years and has recently produced several new world precision benchmarks. A comprehensive review of the field together with recent results and future prospects will be presented.



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