Tübingen 2003 – wissenschaftliches Programm
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HK: Physik der Hadronen und Kerne
HK 28: Elektromagnetische und hadronische Proben IV
HK 28.7: Vortrag
Mittwoch, 19. März 2003, 12:30–12:45, F
High precision eta- meson mass measurement — •Marcel Ulicny and Hartmut Machner — IKP, FZ - Juelich
Particle Data Group estimates the η meson mass as 547.30± 0.12 MeV. The new data of NA48 measurement, not entered in this statistic yet, give value of 547.843±0.051 MeV. This is a measurement with the best precision but differs significantly from PDG mean. An experiment dedicated to the measurement of the η meson mass was done on the accelerator facilities in Forschungszentrum Juelich, Germany. The magnetic spectrometer Big Karl was used to analyze the momenta of the particles obtained in the interactions of protons at 1640 MeV/c beam momentum in 2 mm thick liquid hydrogen target. A calibration measurements with this spectrometer was done in order to obtain all parameters for momentum reconstruction. The η mesons was obtained from the missing mass distribution of 3He from pd→3Heη reaction. The preliminary result of this experiment is Mη=547.64 ± 0.03 ± 0.03 MeV.