Searching for Tensor Currents in the Weak Interaction Using $^{8}$Li $\beta$ Decay

The weak interaction is framed in the Standard Model with a pure vector-axial vector structure. A high-precision measurement of the $\beta-\nu$ correlation coefficient (a$_{\beta\nu}$) could reveal contributions from tensor or scalar currents and give insight into new physics. We utilize stopped $^{8}$Li in the Beta decay Paul Trap (BPT) at Argonne National Lab to measure a$_{\beta\nu}$. The BPT is surrounded on 4 sides with double-sided silicon strip detectors backed by plastic scintillator detectors, which allow the kinematics of the $^{8}$Li decay products to be over-constrained. A previous measurement done by our collaboration resulted in the first improvement in over 50 years to the tensor limit of a$_{\beta\nu}$ in a nuclear setting and was recently published in PRL. We have since upgraded our system and obtained over ten times our previous statistics. Our goal is to achieve a limit of a$_{\beta\nu}$ with an uncertainty of ~0.001. Analysis is ongoing.