Origin of the low-mass electron pair excess in light nucleus-nucleus collisions
Date
2010Author
Krücken, R.Agakichiev, G.
Bałanda, A.
Belver, D.
Belyaev, A. V.
Blanco, A.
Böhmer, M.
Boyard, J. L.
Braun-Munzinger, P.
Cabanelas, Pablo
Castro, E.
Chernenko, S.
Christ, T.
Destefanis, M.
Diáz, 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.
Göbel, K.
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.
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, Yiannis
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, Haralambos
Wagner, V.
Weber, M.
Wisniowski, M.
Wojcik, T.
Wüstenfeld, J.
Yurevich, S.
Zanevsky, Y. V.
Zhou, P.
Source
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy PhysicsVolume
690Issue
2Pages
118-122Google Scholar check
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Show full item recordAbstract
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. © 2010 Elsevier B.V. All rights reserved.