A measurement of the α-β-ν̄ angular correlation in the Gamow-Teller decay Li8→Be*8+ν̄+β, Be*8→ α+α has been performed using ions confined in a linear Paul trap surrounded by silicon detectors. The energy difference spectrum of the α particles emitted along and opposite the direction of the β particle is consistent with the standard model prediction and places a limit of 3.1% (95.5% confidence level) on any tensor contribution to the decay. From this result, the amplitude of any tensor component CT relative to that of the dominant axial-vector component CA of the electroweak interaction is limited to |CT/CA|<0.18 (95.5% confidence level). This experimental approach is facilitated by several favorable features of the Li8 β decay and has different systematic effects than the previous β-ν̄ correlation results for a pure Gamow-Teller transition obtained from studying He6 β decay. © 2013 American Physical Society.
Publication Source (Journal or Book title)
Physical Review Letters
Li, G., Segel, R., Scielzo, N., Bertone, P., Buchinger, F., Caldwell, S., Chaudhuri, A., Clark, J., Crawford, J., Deibel, C., Fallis, J., Gulick, S., Gwinner, G., Lascar, D., Levand, A., Pedretti, M., Savard, G., Sharma, K., Sternberg, M., Sun, T., Van Schelt, J., Yee, R., & Zabransky, B. (2013). Tensor interaction limit derived from the α-β-ν̄ correlation in trapped Li8 ions. Physical Review Letters, 110 (9) https://doi.org/10.1103/PhysRevLett.110.092502