Precision Measurements of ⁸B Beta Decay with the Beta-decay Paul Trap

Pioneering experiments in the 1960s established the Vector – Axial Vector form of the electroweak interaction incorporated into the Standard Model. However, there is no a priori reason that other currents, such as Scalar or Tensor, could not be present. The Gamow-Teller beta decays of ⁸B and ⁸Li have extremely large Q values and the daughter in both cases, ⁸Be, is alpha unbound making these systems exemplary probes of exotic Tensor currents, which would affect the beta-neutrino angular correlation. Improvements over a decade of high-statistics experiments on ⁸B and ⁸Li performed at Argonne National Laboratory using the Beta-decay Paul Trap (BPT) will be presented. In these measurements, the energies of the alpha and beta particles were measured with four 32x32 double-sided silicon strip detectors surrounding the BPT to precisely reconstruct the decay kinematics. The latest work has set the world-leading limit on Tensor currents from a single beta-decay measurement. Furthermore, the high-energy neutrinos observed in solar neutrino astrophysics experiments on Earth predominately originate from ⁸B beta decay in the Sun. Results on determining the ⁸B neutrino energy spectrum, an important input for the astrophysics community, from the same data set will be discussed.