Analysis of the exclusive final state npe+e- in the quasi-free np reaction
Date
2017Author
HADES CollaborationAdamczewski-Musch, J.
Arnold, O.
Atomssa, E. T.
Behnke, C.
Belounnas, Amel
Belyaev, A.
Berger-Chen, J. C.
Biernat, J.
Blanco, A.
Blume, C.
Böhmer, M.
Bordalo, P.
Chernenko, S.
Chlad, L.
Deveaux, C.
Dreyer, J.
Dybczak, A.
Epple, E.
Fabbietti, L.
Fateev, O.
Filip, P.
Fonte, P.
Franco, C.
Friese, J.
Fröhlich, I.
Galatyuk, T.
Garzón, J. A.
Gernhäuser, R.
Golubeva, M.
Guber, F.
Gumberidze, M.
Harabasz, S.
Heinz, T.
Hennino, T.
Hlavac, S.
Höhne, C.
Holzmann, R.
Ierusalimov, A.
Ivashkin, A.
Kämpfer, B.
Karavicheva, T.
Kardan, B.
Koenig, I.
Koenig, W.
Kolb, B. W.
Korcyl, G.
Kornakov, G.
Kotte, R.
Kühn, W.
Kugler, A.
Kunz, T.
Kurepin, A.
Kurilkin, A.
Kurilkin, P.
Ladygin, V.
Lalik, R.
Lapidus, K.
Lebedev, A.
Liu, T.
Lopes, L.
Lorenz, M.
Mahmoud, T.
Maier, L.
Mangiarotti, A.
Markert, J.
Maurus, S.
Metag, V.
Michel, J.
Mihaylov, D. M.
Morinière, E.
Morozov, S.
Müntz, C.
Münzer, R.
Naumann, L.
Nowakowski, K.
Palka, M.
Parpottas, Yiannis
Pechenov, V.
Pechenova, O.
Petousis, Vlassis
Petukhov, O.
Pietraszko, J.
Przygoda, W.
Ramos, S.
Ramstein, B.
Reshetin, A.
Rodriguez-Ramos, P.
Rosier, P.
Rost, A.
Sadovsky, A.
Salabura, P.
Scheib, T.
Schuldes, H.
Schwab, E.
Scozzi, F.
Seck, F.
Sellheim, P.
Siebenson, J.
Silva, L.
Sobolev, Y. G.
Spataro, S.
Ströbele, H.
Stroth, J.
Strzempek, P.
Sturm, C.
Svoboda, O.
Tlusty, P.
Traxler, M.
Tsertos, Haralambos
Usenko, E.
Wagner, V.
Wendisch, C.
Wiebusch, M. G.
Wirth, J.
Zanevsky, Y.
Zumbruch, P.
Sarantsev, A. V.
ISSN
1434-6001Source
European Physical Journal AVolume
53Issue
7Google Scholar check
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Show full item recordAbstract
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25GeV/u impinging on a liquid hydrogen target. Our measurements with HADES confirm a significant excess of e+e- pairs above the π0 mass in the exclusive channel dp→ npe+e-(ps p e c t) as compared to the exclusive channel ppe+e- measured in proton-proton collisions at the same energy. That excess points to different bremsstrahlung production mechanisms. Two models were evaluated for the role of the charged pion exchange between nucleons and double- Δ excitation combined with intermediate ρ-meson production. Differential cross sections as a function of the e+e- invariant mass and of the angles of the virtual photon, proton and electrons provide valuable constraints and encourage further investigations on both experimental and theoretical sides. © 2017, The Author(s).