Limiting Tensor Currents in the Electron-Antineutrino Correlation of Lithium-8 Beta Decay

High-precision measurements of the beta-neutrino correlation coefficient (a) have long been used as a probe for New Physics due to the constant’s sensitivity to scalar and tensor currents, both predicted to be 0 by the Standard Model’s electroweak interaction. With a high Q-value, the delayed alpha emission from the daughter nucleus, and an essentially pure Gamow-Teller structure, the beta decay of Lithium-8 is a highly suitable reaction for measuring a. Utilizing stopped Lithium-8 ions in a Paul Trap surrounded by silicon strip detectors backed with plastic scintillators, the full kinematics of each decay product can be reconstructed. Upon completing the analysis of a high-statistics dataset of 2 million full Lithium-8 decays obtained in 2016, we are well positioned to constrain tensor currents in the weak interaction to approximately 0.2 percent, the most stringent limit yet achieved in the low energy regime.