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Origin of the low-mass electron pair excess in light nucleus-nucleus collisions (2009) |
- Balanda, A.,
- Belver, D.,
- Belyaev, A. V.,
- Blanco, A.,
- Böhmer, M.,
- Boyard, J. L.,
- Braun-Munzinger, P.,
- Cabanelas, P.,
- Castro, E.,
- Chernenko, S.,
- Christ, T.,
- Destefanis, M.,
- Díaz, J.,
- Dohrmann, F.,
- Dybczak, A.,
- Fabbietti, L.,
- Fateev, O. V.,
- Finocchiaro, P.,
- Fonte, P.,
- Friese, J.,
- Fröhlich, I.,
- Galatyuk, T.,
- Garzón, J. A.,
- Gernhäuser, R.,
- Gil, A.,
- Gilardi, C.,
- Golubeva, M.,
- González-Díaz, D.,
- Guber, F.,
- Hennino, T.,
- Holzmann, R.,
- Iori, I.,
- Ivashkin, A.,
- Jurkovic, M.,
- Kämpfer, B.,
- Karavicheva, T.,
- Kirschner, D.,
- Koenig, I.,
- Koenig, W.,
- Kolb, B. W.,
- Kotte, R.,
- Krizek, F.,
- Krücken, R.,
- Kühn, W.,
- Kugler, A.,
- Kurepin, A.,
- Lang, S.,
- Lange, J. S.,
- Lapidus, K.,
- Liu, T.,
- Lopes, L.,
- Lorenz, M.,
- Maier, L.,
- Mangiarotti, A.,
- Markert, J.,
- Metag, V.,
- Michalska, B.,
- Michel, J.,
- Morinière, E.,
- Mousa, J.,
- Müntz, C.,
- Naumann, L.,
- Otwinowski, J.,
- Pachmayer, Y. C.,
- Palka, M.,
- Parpottas, Y.,
- Pechenov, V.,
- Pechenova, O.,
- Pietraszko, J.,
- Przygoda, W.,
- Ramstein, B.,
- Reshetin, A.,
- Rustamov, A.,
- Sadovsky, A.,
- Salabura, P.,
- Schmah, A.,
- Schwab, E.,
- Sobolev, Yu. G.,
- Spataro, S.,
- Spruck, B.,
- Ströbele, H.,
- Stroth, J.,
- Sturm, C.,
- Sudol, M.,
- Tarantola, A.,
- Teilab, K.,
- Tlusty, P.,
- Traxler, M.,
- Trebacz, R.,
- Tsertos, H.,
- Wagner, V.,
- Weber, M.,
- Wisniowski, M.,
- Wojcik, T.,
- Wüstenfeld, J.,
- Yurevich, S.,
- Zanevsky, Y. V.,
- Zhou, P.
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Abstract |
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We report measurements of electron pair production in elementary p+p and d+p reactions at 1.25 GeV/u with the HADES spectrometer. For the first time, the electron pairs were reconstructed for n+p reactions by detecting the proton spectator from the deuteron breakup. We find that the yield of electron pairs with invariant mass Me+e- > 0.15 GeV/c2 is about an order of magnitude larger in n+p reactions as compared to p+p. A comparison to model calculations demonstrates that the production mechanism is not sufficiently described yet. The electron pair spectra measured in C+C reactions are compatible with a superposition of elementary n+p and p+p collisions, leaving little room for additional electron pair sources in such light collision systems..
Comment: 11 pages, 2 figures, \usepackage{epsfig} |
Details der Publikation |
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