Dresden 2000 – scientific programme
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HK: Physik der Hadronen und Kerne
HK 15: Postersitzung / Elektromagnetische und hadronische Proben
HK 15.7: Poster
Thursday, March 23, 2000, 10:15–12:45, B 69
Isospin symmetry breaking in pd→3Hπ+/3Heπ0 reactions — •Andrzej Magiera — Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany
The isospin symmetry breaking measurements in pd→3Hπ+/3Heπ0 reactions are under preparation and first test runs were performed. The energy dependence of the cross section ratio for these reactions at a beam momentum close to 1.57 GeV/c will be measured. The basic idea of this investigation is the isospin symmetry breaking due to π0−η mesons mixing. The beam momentum was choosen to be close to the η meson production threshold, and the 3H/3He cross section ratio should be measured at angles close to 00. Under such conditions the scattering amplitudes of η and π0 production are comparable, giving substantial contribution to isospin symmetry breaking. The method of determining the energy dependence of the ratio of cross sections is based on simultaneous detection of 3H and 3He and thus ensures high accuracy. In order to fulfil those strict requirements the Big Karl spectrometer will be use. It allows the momentum separation of the beam and reaction products, enabling the measurements at small angles. In the test measurements it was shown that the planned experiment is feasible. The relative measurement, expected counting rate and achieved background reduction would allow to reach the accuracy of the cross section ratio of about 2%, what should be compared with the expected 10% variation due to the isospin symmetry breaking.