Dielectron production in $^{12}$C+$^{12}$C collisions at 2 A GeV with HADES

J. Markert , G. Agakishiev , C. Agodi , A. Balanda , G. Bellia , D. Belver , A. Belyaev , A. Blanco , M. Böhmer , J.- L. Boyard (1) , P. Braun-Munzinger , P. Cabanelas , E. Castro , S. Chernenko , T. Christ , M. Destefanis , J. Diaz , F. Dohrmann , A. Dybczak , T. Eberl , L. Fabbietti , O. Fateev , P. Finocchiaro , P. Fonte , J. Friese , I. Fröhlich , T. Galatyuk , J. A. Garzón , R. Gernhäuser , C. Gilardi , M. Golubeva , D. González-Díaz , E. Grosse , F. Guber , M. Heilmann , T. Hennino (1) , R. Holzmann , A. Ierusalimov , I. Iori , A. Ivashkin , M. Jurkovic , B. Kämpfer , K. Kanaki , T. Karavicheva , D. Kirschner , I. Koenig , W. Koenig , B. W. Kolb , R. Kotte , A. Kozuch , F. Krizek , R. Krücken , W. Kühn , A. Kugler , A. Kurepin , J. Lamas-Valverde , S. Lang , J. S. Lange , L. Lopes , L. Maier , A. Mangiarotti , J. Marín , V. Metag , B. Michalska , D. Mishra , E. Morinière (1) , J. Mousa , C. Müntz , L. Naumann , R. Novotny , J. Otwinowski , Y. C. Pachmayer , M. Palka , O. Pechenova , T. Pérez Cavalcanti , J. Pietraszko , W. Przygoda , B. Ramstein (1) , A. Reshetin , M. Roy-Stephan (1) , A. Rustamov , A. Sadovsky , B. Sailer , P. Salabura , A. Schmah , R. Simon , S. Spataro , B. Spruck , H. Ströbele , J. Stroth , C. Sturm , M. Sudol , A. Tarantola , K. Teilab , P. Tlusty , M. Traxler , R. Trebacz , H. Tsertos , I. Veretenkin , V. Wagner , H. Wen , M. Wisniowski , T. Wojcik , J. Wüstenfeld , S. Yurevich , Y. Zanevskyan , P. Zumbruch

1 IPNO - Institut de Physique Nucléaire d'Orsay

We report on a measurement of electron pair production in 12C+12C collisions at an incident energy of 2 GeV per nucleon with the HADES spectrometer. The measured pair production probabilities span over five orders of magnitude from the π0-Dalitz to the ρ/ω invariant-mass region. Dalitz decays of π0 and η account for all the yield up to 0.15 GeV/c2, but for only about 50% above this mass. The excess yield is in agreement with the former DLS result if one assumes that it scales with beam energy like pion production. A preliminary analysis of 12C+12C collisions at an incident energy of 1 A GeV, measured with the HADES detector, supports this scenario.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

J. Markert, G. Agakishiev, C. Agodi, A. Balanda, G. Bellia, et al.. Dielectron production in $^{12}$C+$^{12}$C collisions at 2 A GeV with HADES. QUARK MATTER 2006 - THE 19TH INTERNATIONAL CONFERENCE ON ULTRA-RELATIVISTIC NUCLEUS-NUCLEUS COLLISIONS, Nov 2006, Shanghai, China. pp.S1041-S1045, ⟨10.1088/0954-3899/34/8/S152⟩. ⟨in2p3-00287017⟩