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HK: Fachverband Hadronen und Kerne
HK 10: Accelerators and Instrumentation II
HK 10.1: Group Report
Monday, March 16, 2009, 14:00–14:30, H-ZO 90
PENeLOPE: progress towards a new precise neutron lifetime measurement — •Rüdiger Picker, Igor Altarev, Beatrice Franke, Erwin Gutsmiedl, Joachim Hartmann, Stefan Materne, Axel Müller, Stephan Paul, Rainer Stoepler, and Christian Tietze — Technische Universität München, Physik Department
The neutron lifetime τn allows access to fundamental parameters of the weak interaction. Therefore, a precise knowledge of τn provides direct tests of the Standard Model of particle physics. Moreover, a precise knowledge of the neutron lifetime is important for astrophysical models. However, recent results disagree with the PDG value of 885.7 ± 0.8 s by roughly 6σ. To resolve this discrepancy, we are developing an experiment with a superconducting magnetic trap for ultracold neutrons (UCN) at Technische Universität München. The UCN will be trapped in a multipole field with a flux density of up to 2 T and will be additionally bound to the top by gravitation. This makes extraction and detection of the decay protons possible and allows a direct measurement of the neutron decay rate. The envisaged precision of Δ τn <0.1 s demands very long storage lifetimes and a good handle on systematic effects.. Several measures are taken to avoid these effects or investigate their influence on the extracted lifetime value extensively. The big storage volume of around 700 dm3 and the expected high neutron flux of the UCN source at the FRMII give more than 107 neutrons per filling of the storage volume. The talk will report on the measurement principle and the current status of the setup. Supported by MLL, DPG and the excellence initiative EXC 153.