Köln 2004 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HK: Physik der Hadronen und Kerne

HK 12: Poster Session: Instrumentation and Applications

HK 12.26: Poster

Dienstag, 9. März 2004, 13:30–15:30, Foyer

The spectrometer aSPECT - A Superconducting Spectrometer to analyze the Fundamental Laws of Weak Interaction in Neutron Beta Decay — •Stefan Baeßler¹, Jim Byrne², Ferenc Glück¹, Joachim Hartmann³, Werner Heil¹, Igor Konorov³, Raquel Muñoz Horta¹, Marius Orlowski¹, Gerd Petzoldt¹, Yuri Sobolev¹, Maurits van der Grinten², and Oliver Zimmer³ — ¹Institut für Physik, U. Mainz — ²University of Sussex, Falmer, Brighton, UK — ³Physik Department E18, TU München

Since recently the upper left element of the Cabbibo-Kobayashi- Maskawa-Matrix V_ud can be determined from neutron decay data alone with an accuracy which is comparable to the traditional derivation from nuclear decay data. Both methods agree with each other. However, both values for V_ud, together with V_us and V_ub from high energy physics, violate the unitarity of the Cabbibo-Kobayashi-Maskawa-Matrix by about 2 to 3 sigma. The neutron decay data used for this test is the neutron lifetime τ_n and the beta asymmetry A. Recent determinations of A are not consistent with each other. In the Standard Model, measurements of the neutrino electron correlation coefficient a are equivalent to measurements of A, so that a new measurement of a can either solve the unitarity problem, or it can confirm it with entirely different systematics. In this poster the spectrometer aSPECT is presented. Its purpose is to measure a with a relative accuracy of a few parts per thousand which corresponds to an improvement in A by half an order of magnitude.