%0 Journal Article %T First measurement of low momentum dielectrons radiated off cold nuclear matter %A G. Agakishiev %A A. Balanda %A D. Belver %A A. Belyaev %A J. C. Berger-Chen %A A. Blanco %A M. B£¿hmer %A J. L. Boyard %A P. Cabanelas %A S. Chernenko %A A. Dybczak %A E. Epple %A L. Fabbietti %A O. Fateev %A P. Finocchiaro %A P. Fonte %A J. Friese %A I. Fr£¿hlich %A T. Galatyuk %A J. A. Garz¨®n %A R. Gernh£¿user %A K. G£¿bel %A M. Golubeva %A D. Gonz¨¢lez-D¨ªaz %A F. Guber %A M. Gumberidze %A T. Heinz %A T. Hennino %A R. Holzmann %A A. Ierusalimov %A I. Iori %A A. Ivashkin %A M. Jurkovic %A B. K£¿mpfer %A T. Karavicheva %A I. Koenig %A W. Koenig %A B. W. Kolb %A G. Kornakov %A R. Kotte %A A. Kr¨¢sa %A F. Krizek %A R. Kr¨¹cken %A H. Kuc %A W. K¨¹hn %A A. Kugler %A A. Kurepin %A V. Ladygin %A R. Lalik %A S. Lang %A K. Lapidus %A A. Lebedev %A T. Liu %A L. Lopes %A M. Lorenz %A L. Maier %A A. Mangiarotti %A J. Markert %A V. Metag %A B. Michalska %A J. Michel %A D. Mishra %A C. M¨¹ntz %A L. Naumann %A Y. C. Pachmayer %A M. Palka %A Y. Parpottas %A V. Pechenov %A O. Pechenova %A J. Pietraszko %A W. Przygoda %A B. Ramstein %A A. Reshetin %A A. Rustamov %A A. Sadovsky %A P. Salabura %A A. Schmah %A E. Schwab %A J. Siebenson %A Yu. G. Sobolev %A S. Spataro %A B. Spruck %A H. Str£¿bele %A J. Stroth %A C. Sturm %A A. Tarantola %A K. Teilab %A P. Tlusty %A M. Traxler %A R. Trebacz %A H. Tsertos %A T. Vasiliev %A V. Wagner %A M. Weber %A C. Wendisch %A J. W¨¹stenfeld %A S. Yurevich %A Y. Zanevsky %J Physics %D 2012 %I arXiv %R 10.1016/j.physletb.2012.08.004 %X We present data on dielectron emission in proton induced reactions on a Nb target at 3.5 GeV kinetic beam energy measured with HADES installed at GSI. The data represent the first high statistics measurement of proton-induced dielectron radiation from cold nuclear matter in a kinematic regime, where strong medium effects are expected. Combined with the good mass resolution of 2%, it is the first measurement sensitive to changes of the spectral functions of vector mesons, as predicted by models for hadrons at rest or small relative momenta. Comparing the e+e invariant mass spectra to elementary p+p data, we observe for e+e momenta Pee < 0.8 GeV/c a strong modification of the shape of the spectrum, which we attribute to an additional rho-like contribution and a decrease of omega yield. These opposite trends are tentatively interpreted as a strong coupling of the rho meson to baryonic resonances and an absorption of the omega meson, which are two aspects of in-medium modification of vector mesons. %U http://arxiv.org/abs/1205.1918v2