Abstract
Measurements of the ft values for T=1/2 mirror $\beta$+ decays offer a method to test the conserved vector current hypothesis and to determine Vud, the up-down matrix element of the Cabibbo-Kobayashi-Maskawa matrix. In most mirror decays used for these tests, uncertainties on the ft values are dominated by the uncertainties in the half-lives. Two precision half-life measurements were performed for the T=1/2 $\beta$+ emitters, 17F and 33Cl, in order to eliminate the half-life as the leading source of uncertainty in their ft values. \item[Method] Half-lives of 17F and 33Cl were determined using $\beta$ counting of implanted radioactive ion beam samples on a moving tape transport system at the SPIRAL low energy identification station at GANIL. The 17F half-life result, 64.347~(35) s, precise to $\pm$0.05 %, is a factor of 5 times more precise than the previous world average. The half-life of 33Cl was determined to be 2.5038~(22) s. The current precision of $\pm$0.09 % is nearly 2 times more precise compared to the previous world average. The precision achieved during the present measurements implies that the half-life no longer dominates the uncertainty of the ft values for both T=1/2 mirror decays 17F and 33Cl.
Highlights
High-precision measurements of T = 1/2 mirror β+ decay f t values between isobaric analog states are used for testing the conserved vector current (CVC) hypothesis, to discriminate between theoretical models that describe isospin symmetry breaking, and for providing stringent tests of the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix for limiting possible extensions to the standard model description of electroweak interactions
In most mirror decays used for these tests, uncertainties in the f t values are dominated by the uncertainties in the half-lives
The precision achieved during the present measurements implies that the half-life no longer dominates the uncertainty of the f t values for both T = 1/2 mirror decays 17F and 33Cl
Summary
Measurements of the f t values for T = 1/2 mirror β+ decays offer a method to test the conserved vector current hypothesis and to determine Vud, the up-down matrix element of the Cabibbo-Kobayashi-Maskawa matrix. In most mirror decays used for these tests, uncertainties in the f t values are dominated by the uncertainties in the half-lives. Results: The 17F half-life result, 64.347 (35) s, precise to ±0.05%, is a factor of 5 times more precise than the previous world average. The current precision of ±0.09% is nearly 2 times more precise compared to the previous world average. Conclusions: The precision achieved during the present measurements implies that the half-life no longer dominates the uncertainty of the f t values for both T = 1/2 mirror decays 17F and 33Cl
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
