Bochum 2009 – wissenschaftliches Programm
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HK: Fachverband Hadronen und Kerne
HK 67: Poster Session
HK 67.29: Poster
Donnerstag, 19. März 2009, 14:00–16:00, Audi-Max
Progress in Pseudo-Scalar Meson Photoproduction Experiments at MAMI-C in Mainz. — John R M Annand, David J Hamilton, David Howdle, Ken Livingston, •Ian James Douglas MacGregor, Joe Mancell, Eilidh McNicoll, Jamie Robinson, and Günther Rosner — Department of Physics and Astronomy, University of Glasgow, Glasgow UK
Since its upgrade in 2007, the Glasgow-Mainz spectrometer has provided a state-of-the-art photon tagger for a series of photo-production experiments at electron beam energies from 200 to 1508 MeV. We report on the operational status of the tagging spectrometer, refitted with a new focal-plane detector to extend its rate capability and improve its timing resolution by a factor 2. This complements the Crystal Ball and TAPS calorimeters, which provide almost 4π detection of both neutral and charged particles. These systems have very high detection efficiency for multi-photon final states. Measurement of pseudo-scalar-meson photo production on the nucleon is a major component of the experimental programme. We have data on π0, π+,η, η′, K0, K+ (single and multiple-meson) final states for 1H and 2H targets. The eventual goal is to make complete measurements of the helicity amplitudes, which require at least 8 observables chosen properly from unpolarised, single-spin and double-spin possibilities. The possibilities in Mainz will extend when polarised targets become available in 2009. In December 2008 the maximum MAMI-C energy was raised to 1557 MeV and data taken with an open trigger at tagged-photon energies from 80 to 1447 MeV. We show some first analyses of these tests.