Tensor interaction limit derived from the α-ß-ν[over ¯] correlation in trapped 8Li ions.

ABSTRACT

A measurement of the α-ß-ν[over ¯] angular correlation in the Gamow-Teller decay (8)Li→(8)Be(*)+ν[over ¯]+ß, (8)Be(*)→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 ß 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 C(T) relative to that of the dominant axial-vector component C(A) of the electroweak interaction is limited to |C(T)/C(A)|<0.18 (95.5% confidence level). This experimental approach is facilitated by several favorable features of the (8)Li ß decay and has different systematic effects than the previous ß-ν[over ¯] correlation results for a pure Gamow-Teller transition obtained from studying (6)He ß decay.