Neutron beta decay studies at the Institut Laue-Langevin

In the frame of the electroweak Standard Model of particle physics, neutron beta decay is described by only two parameters: the element V-ud of the weak quark mixing matrix (CKM matrix) and the ratio lambda = g(A)/g(V) of the weak coupling constants of the neutron. Experimentally, a larger number of neutron decay parameters are accessible. These are the lifetime and various correlation coefficients between the spins and momenta of the particles involved in neutron decay. Hence, the problem is strongly overdetermined, and many tests going beyond the Standard Model are possible. These comprise tests of the unitarity of the CKM matrix, tests for tensor and scalar admixtures, searches for right-handed currents within the frame of left-right symmetric models, as well as tests of time reversal symmetry. During the past years various groups working in this field have made considerable progress in neutron decay experimentation. in our presentation we shall give a survey on new experiments performed at the Institut Laue-Langevin, Grenoble, France, and on the results concerning the Standard Model.