The differential cross section has been measured for the reaction γ +p→ π o + p at the Bonn 2.5 GeV electron synchrotron in the energy range from 0.55 to 2.2 GeV at a c.m.angle of 120 degrees.
No description provided.
At the Bonn 2.5 GeV electron synchrotron the angular distribution of the target asymmetry T = (σ↑ − σ↓) (σ↑ + σ↓) for the reaction γp↑ → π + n was measured at a mean photon energy of 700 MeV and pion CM-angles from 50° to 155°. The combination of a 3 He-cryostat, polarizing the free protons in the target up to 65%, with a large acceptance magnet for pion detection led to statistical errors of the target asymmetry comparable with those of cross section measurements.
No description provided.
The target asymmetry for the reaction γ p → K + Λ 0 was measured at the Bonn 2.5 GeV synchroton. Data were taken at a fixed kaon c.m. angle of 90° and at photon energies between 1.1 and 1.3 GeV. The kaons were detected in a large aperture magnetic spectrometer.
5 PCT TARGET POLARIZATION UNCERTAINTY INCLUDED IN QUOTED ERRORS.
At the Bonn 2.5 GeV synchrotron the polarization of the Λ 0 was measured at 40° and 90° for three energies. The kaon was detected with a strong focussing magnetic spectrometer and separated from other particles with the help of a differential liquid Čerenkov counter. The polarization was determined by means of the angular distribution of the decay proton which was measured with a combination of sonic spark chambers and a scintillation counter hodoscope. The typical statistical errors are about 13%. The systematic errors add up to 8%.
No description provided.
At the Bonn 2.5.GeV electron synchrotron the target asymmetry for the photoproduction of positive pions has been measured. Data were taken at photon energies between 0.7 and 2.2 GeV and a pion CM-angle of 65°.
Axis error includes +- 0.0/0.0 contribution (?////).
No description provided.
We report the measurement of the differential cross section of the reaction γ +p→π0 +p at a photon energy of 1.4 GeV and pion c.m. angles between 60 and 175 degrees. The angular distribution confirms the simple quark model prediction of a pure magnetic excitation of theF37 (1950) resonance.
No description provided.
At the Bonn 2.5 GeV electron synchrotron we have measured the differential cross section of the reaction γp→π0p at a pion CM angle of 170° and at photon energiesKγ between 0.6 and 1.8 GeV. In comparison to previous measurements the accuracy of the data was improved substantially. For the first time in neutral pion photoproduction a cusp structure at the η-threshold has been confirmed [1].
No description provided.
Measurements of the target asymmetry T = ( σ ↑ − σ ↓)/( σ ↑ + σ ↓) for the reactions γ p → π + n and γ n → π − p at a fixed photon energy of 850 MeV and pion c.m. angles between 70° and 150° are reported. The data are compared to the previously measured angular distribution at 700 MeV.
No description provided.
No description provided.
A polarized neutron target was used at the Bonn 2.5 GeV Synchrotron to measure the target asymmetry for the reaction γ n↑→ π − p at a fixed photon energy of 700 MeV and pion c.m. angles between 50° and 140°. The pions were detected in a large aperture magnetic spectrometer. The data show a structure which is quite different from the distribution previously measured for the reaction γ p↑→ π + n.
No description provided.
The target asymmetry of the deuteron photodisintegration was measured at a photon energy of 550±50 MeV and at proton center-off-mass angles between 25 and 155 degrees.D-butanol andND3 were used as target material yielding a maximum deuteron polarization of 41%. Proton and neutron were detected in coincidence. The data show a structure which cannot be described by the existing analyses.
Axis error includes +- 8/8 contribution (UNCERTAINTY IN THE DETERMINATION OF THE TARGET POLARIZATION//OTHER SYSTEMATIC ERRORS ARE FROM COMPETING PROCESSES (<2 PCT) AND OTHERS (<1 PCT)).