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The 1 2 + → 1 2 + superallowed mixed mirror decay of 19 Ne to 19 F is excellently suited for high precision studies of the weak interaction. However, there is some disagreement on the value of the half-life. In a new measurement we have determined this quantity to be T 1/2 = 17.2832 ± 0.0051 (stat) ± 0.0066 (sys) s, which differs from the previous world average by 3 standard deviations. The impact of this measurement on limits for physics beyond the standard model such as the presence of tensor currents is discussed.PACS numbers: 24.80.+y,12.15.Hh, We can precisely characterize the structure of the weak interaction and probe for physics Beyond the Standard Model (BSM) in nuclear beta decay by searching for a deviation from unitarity of the Cabibbo-KobayashiMaskawa (CKM) matrix, and by constraining the presence of new, exotic interactions which would manifest as scalar or tensor couplings. Currently, the thirteen, purely vector, superallowed 0 + → 0 + Fermi decays provide the most precise determination of the CKM matrix element governing nuclear beta decay, |V ud | = 0.97425(22), and the most stringent constraint on scalar couplings from the constancy of the Ft values [1]. The superallowed, mixed Fermi/Gamow-Teller transitions between T = 1 2 mirror nuclei can provide a needed cross check of the nucleus dependent theoretical corrections which contribute significantly to the overall uncertainty, and have been used to extract |V ud | = 0.9719 (17) [2], where the 19 Ne system is the most precise component. The 19 Ne system is capable of very sensitive tests for right-handed currents due to the very small beta asymmetry [3], and we show that it can be used to obtain complementary limits on tensor couplings.Mixed decays require a measurement of the half-life and an angular correlation to perform SM tests, in order to fix the Fermi/Gamow-Teller mixing ratio ρ. Until recently, the uncertainty in the 19 Ne half-life determination was several times higher than all other contributions to the uncertainty in the Ft value, and was on par with the contribution of the beta asymmetry parameter to the uncertainty of V ud . There is some disagreement between the published values of the lifetime, represented by a χ 2 /NDF of 41.2/7 for the global data set. This discrepancy has been addressed in our experiment through a novel approach which addressed with improved relia-

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