Using Triumf's neutral atom trap, Trinat, for nuclear β decay, we have measured the β asymmetry with respect to the initial nuclear spin in ^{37}K to be A_{β}=-0.5707(13)_{syst}(13)_{stat}(5)_{pol}, a 0.3% measurement. This is the best relative accuracy of any β-asymmetry measurement in a nucleus or the neutron, and is in agreement with the standard model prediction -0.5706(7). We compare constraints on physics beyond the standard model with other β-decay measurements, and improve the value of V_{ud} measured in this mirror nucleus by a factor of 4.

We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37 K atoms which will allow us to precisely measure angular correlation parameters in the b + -decay of the same atoms. These results will be used to test the V−A framework of the weak interaction at high precision. At the TRIUMF neutral atom trap (TRINAT), a magneto-optical trap confines and cools neutral 37 K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of¯=  P 0.9913 0.0009, which is significantly more precise than previous measurements with this technique. Since our current measurement of the β-asymmetry has 0.2% statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to <0.1%, allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.

The half-life of 37 K has been measured to be 1.23651(94) s, a value nearly an order of magnitude more precise than the best previously reported. The β + decay of 37 K occurs mainly via a superallowed branch to the ground-state of its T = 1/2 mirror, 37 Ar. This transition has been used recently, together with similar transitions from four other nuclei, as an alternative test of CVC and method for determining V ud , but the precision of its f t value was limited by the relatively large half-life uncertainty. Our result corrects that situation. Another motivation for improving the f t value was to determine the standard-model prediction for the β-decay correlation parameters, which will be compared to those currently being measured by the Trinat collaboration at Triumf. The new f t value, 4605(8) s, is now limited in precision by the 97.99(14)% ground-state branching ratio.

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The Texas A&M University Penning Trap facility is an upcoming ion trap that will be used to search for possible scalar currents in T = 2 superallowed β-delayed proton decays, which, if found, would be an indication of physics beyond the standard model. In addition, TAMUTRAP will provide a low-energy, point-like source of ions for various other applications at the Cyclotron Institute. The experiment is centered around a unique, compensated cylindrical Penning trap that employs a specially optimized length/radius ratio in the electrode structure that is not used by any other facility. This allows the geometry to exhibit an unprecedented 90 mm free radius, which is larger than in any existing trap, while at the same time remaining a tractable overall length. The trap geometry was designed from first principles to be suitable for a wide range of nuclear physics experiments. In particular, the electrode structure is both "tunable" and "orthogonalized", which allows for a near quadrupole electric field at the trap center, a feature necessary for performing precision mass measurements. β + 0 + , T = 2 γ p 0 + , T = 2