1. Identification of baryon resonances in central heavy-ion collisions at energies between 1 and 2 AGeV
- Author
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Eskef, M., Pelte, D., Goebels, G., Haefele, E., Herrmann, N., Korolija, M., Leifels, Y., Merlitz, H., Mohren, S., Stockmeier, M.R., Trzaska, M., Alard, J-P., Andronic, A., Averbeck, R., Basrak, Z., Bastid, N., Belyaev, I., Best, D., Buta, A., Caplar, R., Cindro, N., Coffin, J.P., Crochet, P., Dupieux, P., Dzelalija, M., Fraysse, L., Fodor, Z., Genoux-Lubain, A., Gobbi, A., Hildenbrand, K.D., Hong, B., Jundt, F., Kecskemeti, J., Kirejczyk, M., Kotte, R., Kutsche, R., Lebedev, A., Manko, V., Moesner, J., Moisa, D., Neubert, W., Petrovici, M., Pinkenburg, C., Plettner, C., Pras, P., Rami, F., Ramillien, V., Reisdorf, W., Ritman, J.L., de Schauenburg, B., Schuell, D., Seres, Z., Sikora, B., Simion, V., Siwek-Wilczynska, K., Smolyankin, V., Vasiliev, M.A., Wagner, P., Wang, G.S., Wisniewski, K., Wohlfarth, D., Zhilin, A., Laboratoire de Physique Corpusculaire - Clermont-Ferrand (LPC), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and FOPI
- Subjects
25.75.-q Relativistic heavy-ion collisions - 14.20.Gk Baryon resonances with S=0 ,[PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex] ,Nuclear Experiment - Abstract
The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the pt spectra of charged pions by a method which does not depend on a specific resonance shape. In addition the mass distribution of resonances are obtained from the invariant masses of (p,π±) pairs. With both methods the deduced mass distribution are shifted by an average value of -60 MeV/c2 relative to the mass distribution of the free Δ(1232) resonance, the distribution descent almost exponentially towards mass values of 2000 MeV/c2. The observed differences between (p,π-) and (p,π+) pairs indicate a contribution of isospin I=1/2 resonances. The attempt to consistently describe the deduced mass distributions and the reconstructed kinetic energy spectra of the resonances leads to new insights about the freeze out conditions, i.e. to rather low temperatures and large expansion velocities.
- Published
- 1998
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