Tensor limits from the beta-neutrino correlation in the decay of 8Li
Guy Savard
Argonne National Laboratory
A measurement of the α-β-ν angular correlation in the beta decay of 8Li has been performed using 8Li ions confined in a linear Paul trap surrounded by an array of four sets of silicon detectors. This decay follows the sequence 8Li → 8Be*+ν+β →α+α+ν+β and the trapped 8Li sample floating at rest in the center of the detector array provides an ideal configuration for a full reconstruction of the events. Using this system, a new limit on the contribution of an intrinsic tensor component to the electroweak interaction has been determined by measuring the energy difference spectrum of the α particles emitted along the direction of the β particle (PRL 115, 182501, 2015). New measurements with improved statistics and reduced systematics are ongoing to further extend this limit. Theoretical uncertainties on recoil order corrections appear to be the remaining main source of systematic errors and ways to address those will also be presented.