We report a new precision half-life measurement of 17 F, using the β-counting station at the University of Notre Dame. The measured value of t new 1/2 = 64.402(42) s is in agreement with several past measurements and represents one of the most precise measurements to date. In anticipation of future measurements of the correlation parameters for the decay and using the new world average t world 1/2 = 64.398(61) s, we present a new estimate of the mixing ratio ρ for the mixed transition as well as the correlation parameters based on assuming Standard Model validity.

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Thanks to extensive experimental efforts that led to a precise determination of the various superallowed 0 + → 0 + pure Fermi transition experimental quantities, we now have a very precise value for V ud that leads to a stringent test of the CKM matrix unitarity. Despite this achievement, measurements in other less precise systems remain relevant as conflicting results could uncover unknown systematic effects or even new physics. One such system is the superallowed mixed transition, which can help refine the same theoretical corrections used for pure Fermi transitions and hence improve the accuracy of V ud. However, as a corrected F t-value determination from these systems requires the more challenging determination of the Fermi Gamow-Teller mixing ratio, only five transitions, spreading from 19 Ne to 37 K, are currently fully characterized. There are several ongoing efforts to determine the mixing ratios for medium-mass nuclei. Measuring transitions in lighter nuclei, such as 17 F, 15 O, 13 N and 11 C, poses new challenges as their longer half-lives, ranging from 1 to 22 minutes, conflict with the time constraints present at the large radioactive ion beam facilities where these nuclei are typically produced. We will present a proposed ion trapping experiment to measure these transitions at the University of Notre Dame where time constraints are less stringent.