Open Access

Manuel Lorenz, Geydar Agakishiev, Claudia Behnke, Daniel Belver, Alexei V. Belyaev, Jia-Chii Berger-Chen, Alberto Blanco, Christoph Blume, Michael Böhmer, Pablo Cabanelas Eiras, Sergey P. Chernenko, Christina Dritsa, Adrian Dybczak, Eliane Epple, Laura Fabbietti, Oleg Fateev, Paulo Fonte, Jürgen Friese, Ingo Fröhlich, Tetyana Galatyuk, Juan A. Garzón, Katharina Gill, Marina Golubeva, Diégo González-Díaz, Fedor Guber, Malgorzata Gumberidze, Szymon Harabasz, Thierry Hennino, Claudia Höhne, Romain Holzmann, Patrick Huck, Alexander P. Ierusalimov, Alexander Ivashkin, Martin Jurkovič, Burkhard Kämpfer, Tatiana L. Karavicheva, Ilse Koenig, Wolfgang Koenig, Burkhard W. Kolb, Grzegorz Korcyl, Georgy Kornakov, Roland Kotte, Antonin Krása, Erik Krebs, Filip Krizek, Hubert Kuc, Andrej Kugler, Alexander Kurepin, Aleksey K. Kurilkin, Pavel Kurilkin, Vladimir P. Ladygin, Rafał Tomasz Lalik, Simon Martin Lang, Kirill Lapidus, Alexei Lebedev, Luis Alberto Vieira Lopes, Ludwig W. Maier, Alessio Mangiarotti, Jochen Markert, Volker Metag, Jan Michel, Christian Müntz, Robert Helmut Münzer, Lothar Naumann, Marek Palka, Yannis Parpottas, Vladimir Pechenov, Olga Pechenova, Jerzy Pietraszko, Witold Przygoda, Béatrice Ramstein, Laura Rehnisch, Andrey Reshetin, Anar Rustamov, Alexander Sadovsky, Piotr Salabura, Timo Scheib, Heidi Schuldes, Johannes Stephan Siebenson, Yuri G. Sobolev, Stefano Spataro, Herbert Ströbele, Joachim Stroth, Paweł Strzempek, Christian Thomas Sturm, Ondřej Svoboda, Attilio Tarantola Peloni, Khaled Teilab, Pavel Tlustý, Michael Traxler, Haralabos Tsertos, Taras A. Vasiliev, Vladimir Wagner, Michael Weber, Christian Wendisch, Jörn Wüstenfeld, Sergey Yurevich, Yuri V. Zanevsky

• The High Acceptance DiElectron Spectrometer HADES [1] is installed at the Helmholtzzentrum für Schwerionenforschung (GSI) accelerator facility in Darmstadt. It investigates dielectron emission and strangeness production in the 1-3 AGeV regime. A recent experiment series focusses on medium-modifications of light vector mesons in cold nuclear matter. In two runs, p+p and p+Nb reactions were investigated at 3.5 GeV beam energy; about 9·109 events have been registered. In contrast to other experiments the high acceptance of the HADES allows for a detailed analysis of electron pairs with low momenta relative to nuclear matter, where modifications of the spectral functions of vector mesons are predicted to be most prominent. Comparing these low momentum electron pairs to the reference measurement in the elementary p+p reaction, we find in fact a strong modification of the spectral distribution in the whole vector meson region.