Michael Ostrick

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First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the(More)
The COMPASS experiment at the CERN SPS has studied the diffractive dissociation of negative pions into the π- π- π+ final state using a 190  GeV/c pion beam hitting a lead target. A partial wave analysis has been performed on a sample of 420,000 events taken at values of the squared 4-momentum transfer t' between 0.1 and 1  GeV2/c2. The well-known(More)
Abstract. The reactions γ p → K Λ and γ p → K Σ were measured in the energy range from threshold up to a photon energy of 2.6 GeV. The data were taken with the SAPHIR detector at the electron stretcher facility, ELSA. Results on cross sections and hyperon polarizations are presented as a function of kaon production angle and photon energy. The total cross(More)
Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of approximately 98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of(More)
Anterior radial keratotomy was performed with a diamond blade in ten rhesus monkey eyes. Results were compared with those of a previous study in which a metal blade was used. Histologic assessment showed endothelial degeneration, but fewer edematous endothelial cells, than in the previous study. Specular microscopy demonstrated statistically significant(More)
The photoproduction of η-mesons off different nuclei has been measured with the CBELSA/TAPS detector system for incident photon energies between 1500 2200 MeV. The transparency ratio has been deduced and compared to theoretical calculations describing the propagation of η-mesons in nuclei. The comparison indicates a width of the η-meson of the order of Γ =(More)
The photoproduction of omega mesons on nuclei has been investigated using the Crystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The aim is to study possible in-medium modifications of the omega meson via the reaction gamma + A --> omega + X --> pi(0)gamma + X('). Results obtained for Nb are compared to a reference measurement on a(More)
The reaction γp → pπη has been studied with the CBELSA detector at the tagged photon beam of the Bonn electron stretcher facility. The reaction shows contributions from ∆(1232)η, N(1535)π and pa0(980) as intermediate states. A partial wave analysis suggests that the reaction proceeds via formation of six ∆ resonances, ∆(1600)P33, ∆(1920)P33, ∆(1700)D33 ,(More)
Precise angular distributions have been measured for the first time for the photoproduction of π0 mesons off neutrons bound in the deuteron. The effects from nuclear Fermi motion have been eliminated by a complete kinematic reconstruction of the final state. The influence of final-state-interaction effects has been estimated by a comparison of the reaction(More)