Measurements of the Longitudinal Electron Polarization in Nuclear Beta-Decay

Abstract

One important consequence of the maximum violation of parity in nuclear ß-decay and the pure V-A-interaction is the resulting longitudinal polarization P of the emitted electrons with P = -v/c. Deviations from this value can be caused by:

• a.) the mechanism of the weak interaction itself (non-maximum violation of parity, Fierz-interference etc.),

• b.) nuclear structure — and renormalization effects (admixtures of the strong interaction).

According to b.) measurements of the longitudinal polarization of β-decay electrons can yield information about the magnitude of these effects (described by form-factors) and in conjunction with a proper nuclear model about the β-matrix elements. In contrast to measurements for a.) which have to be absolute our measurements concerning b.) could be done relative to the well-known transition of ⁶⁰Co. Keeping in mind the relativeness of our results one can, however, deduce values for Fierz-interference or contributions from right-handed currents for different types of β-transitions.