Searching for Tensor Currents in the Weak Interaction in the β-decay of ⁸Li and ⁸B

The weak interaction of the Standard Model is well-described by a vector-axial vector, or ‘V-A’, structure, which reproduces both maximal parity violation and left-handed neutrinos in beta-decay. However, there is no first-principles reason that other the interactions, such as scalar (S) or tensor (T), may not be present. To search for possible tensor contributions to the weak interaction we measure the beta-neutrino correlation coefficient a_βν in the Gamow-Teller beta-decays of ⁸Li and ⁸B. The A = 8 decays are ideal to probe a_βν due to the large Q-value and delayed alpha emission from the excited state ⁸Be. These measurements are performed with the Beta decay Paul Trap (BPT) at Argonne National Lab. The BPT is surrounded on 4 sides with double-sided silicon strip detectors backed by plastic scintillator detectors, which allow the kinematics of decay products from the trapped mass-8 ions to be over-constrained. In this presentation we will present the high precision results form ⁸Li and the first results from the decay of ⁸B.