2020 Impact factor 3.043
Hadrons and Nuclei
Eur. Phys. J. A 16, 127-137 (2003)
DOI: 10.1140/epja/i2002-10079-7

Measurement of the $\mth{\eta}$ production in proton-proton collisions with the COSY time-of-flight spectrometer

M. Abdel-Bary1, S. Abdel-Samad1, R. Bilger2, K.-Th. Brinkmann3, H. Clement2, S. Dshemuchadse4, E. Dorochkevitch2, H. Dutz5, W. Eyrich6, A. Erhardt2, D. Filges1, A. Filippi7, H. Freiesleben3, M. Fritsch6, R. Geyer1, A. Gillitzer1, D. Hesselbarth1, B. Jakob3, L. Karsch3, K. Kilian1, H. Koch8, J. Kreß2, E. Kuhlmann3, S. Marcello7, S. Marwinski1, S. Mauro8, W. Meyer8, P. Michel4, K. Möller4, H. P. Morsch1, L. Naumann4, N. Paul1, M. Richter3, E. Roderburg1, M. Rogge1, A. Schamlott4, M. Schmitz1, P. Schönmeier3, M. Schulte-Wissermann3, W. Schroeder6, T. Sefzick1, F. Stinzing6, G.Y. Sun3, G.J. Wagner2, M. Wagner6, A. Wilms8, P. Wintz1, S. Wirth6 and P. Zupranski9

1  Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany
2  Physikalisches Institut, Universität Tübingen, D-72076 Tübingen, Germany
3  Institut für Kern- und Teilchenphysik, Technische Universität Dresden, D-01062 Dresden, Germany
4  Institut für Kern- und Hadronenphysik, Forschungszentrum Rossendorf, D-01314 Dresden, Germany
5  Physikalisches Institut, Universität Bonn, D-53115 Bonn, Germany
6  Physikalisches Institut, Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany
7  INFN Torino, I-10125 Torino, Italy
8  Institut für Experimentalphysik, Universität Bochum, D-44780 Bochum, Germany
9  Andrzej Soltan Institute for Nuclear Studies, PL-00681 Warsaw, Poland

e.roderburg@fz-juelich.de

(Received: 24 May 2002 / Revised version: 20 September 2002 / Published online: 17 January 2003)

Abstract
The reaction $pp \rightarrow pp\eta$ was measured at excess energies of 15 and 41 MeV at an external target of the Jülich Cooler Synchrotron COSY with the time-of-flight spectrometer. About 25000 events were measured for the excess energy of 15 MeV and about 8000 for 41 MeV. Both protons of the process $pp\eta$ were detected with an acceptance of nearly 100% and the $\eta$ was reconstructed by the missing-mass technique. For both excess energies the angular distributions are found to be nearly isotropic. In the invariant-mass distributions strong deviations from the pure phase space distributions are seen.

PACS
25.40.Ve - Other reactions above meson production thresholds (energies 400 MeV).
13.75.Cs - Nucleon-nucleon interactions (including antinucleons, deuterons, etc.).
14.40.Aq - $\pi$, K, and $\eta$ mesons.

© Società Italiana di Fisica, Springer-Verlag 2003