München 2006 – scientific programme
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HK: Physik der Hadronen und Kerne
HK 37: Kern- und Teilchen-Astrophysik
HK 37.5: Talk
Wednesday, March 22, 2006, 17:30–17:45, E
A Measurement of the Neutrino Asymmetry B in Neutron Decay — •Marc Schumann1, Hartmut Abele1, Marc Deissenroth1, Michael Kreuz2, and Torsten Soldner2 — 1Physikalisches Institut, Universität Heidelberg — 2Institut Laue-Langevin (ILL), Grenoble
Parity is maximally violated in the Standard Model of weak interaction. Incomplete parity violation would modify the neutrino helicity in particular and would be a hint for “new physics”.
The Neutrino Asymmetry B is the correlation between anti-neutrino momentum and neutron spin in the decay of polarized neutrons. This quantity is very sensitive to the neutrino helicity since the Standard Model predicts the anti-neutrino to be emitted anti-parallel to its spin direction. We have measured B with the electron spectrometer PERKEO II at the high flux reactor of the Institut Laue-Langevin (ILL). The instrument was equipped with a combined electron-proton detector in order to measure both particles in coincidence to allow a reconstruction of the neutrino. We will report on the experiment that can also be analyzed to extract the proton asymmetry C and present first results.