Tests of the standard model with the spectrometer PERKEO II

The results of measurements of the beta asymmetry A = -0.1189(12) in the decay of free neutrons are discussed. The measurements are conducted using the PERKEO II spectrometer. The neutrons are polarized by a supermirror polarizer, then pass a collimation system and enter the decay volume. In the decay volume a magnetic field (B ≅ 1 T) separates the decay neutrons: some gyrated in the direction of the magnetic field, the others in the opposite direction. The prospects for improving the experimental installation in order to refine this result and provide capabilities for measuring the weak magnetism term k and the neutrino asymmetry B are considered as well. The results obtained are used for verification of the standard model of the elementary particles and their interactions. It is shown that the neutron decay may be described as an interaction between a hadronic and a leptonic current each consisting of a vector and an axial vector part. The vector part is considered to be conserved. The axial vector part of the hadronic current is renormalized by a constant λ. The best way to find λ experimentally is to measure the beta asymmetry A in the decay of free polarized neutrons. With the result values for the other coupling constants in the same process, the neutrino asymmetry B and the electron neutrino correlation coefficient a are also fixed. A comparison of their predicted values with experimental ones tests the consistency of the theory