Berlin 2005 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 13: Kern- und Teilchen-Astrophysik
HK 13.8: Vortrag
Freitag, 4. März 2005, 18:45–19:00, TU MA144
The Neutrino Asymmetry B and the Proton Asymmetry C in Neutron Decay — •Marc Schumann1, Hartmut Abele1, Stefan Baeßler2, Marc Deissenroth1, Jochen Krempel1, Michael Kreuz3, Bastian Märkisch1, Daniela Mund1, Alexandre Petoukhov3, and Torsten Soldner3 — 1Physikalisches Institut, Universität Heidelberg — 2Institut für Physik, Universität Mainz — 3Institut Laue-Langevin (ILL), Grenoble
The β-decay of the free cold neutron is an unique system to perform precision measurements on the structure of the weak interaction since corrections are very small. Correlation coefficients between the decay products may give hints on physics beyond the standard model, such as the electron asymmetry A and the proton asymmetry C test the unitarity of CKM-matrix. Both, the neutrino asymmetry B and the coefficient A are sensitive to admixtures of right handed currents.
We have measured the asymmetries B and C, i.e. the correlations between neutron spin and the momentum of neutrino or proton. The spectrometer PERKEO II was equipped with a combined electron-proton detector allowing us to reconstruct the neutrino momentum and to measure both asymmetries simultaneously. The experiment was carried out at the cold polarised neutron beam facility PF1b of the ILL in 2004. Systematic uncertainties of former PERKEO B measurements have been reduced considerably.
We will give a brief report on the experiment and its motivation and present first results.