%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