학술논문
Low-mass lepton pair production in Pb-Au collisions at 40 A.GeV
Document Type
Original Paper
Author
Adamová, D.; Agakichiev, G.; Appelshäuser, H.; Belaga, V.; Braun-Munzinger, P.; Cherlin, A.; Damjanović, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S. I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glässel, P.; Hering, G.; Holeczek, J.; Kushpil, V.; Lenkeit, B.; Maas, A.; Marín, A.; Milosević, J.; Milov, A.; Miśkowiec, D.; Panebrattsev, Y.; Petchenova, O.; Petrácek, V.; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Richter, M.; Sako, H.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Seipp, W.; Shimansky, S.; Slívová, J.; Specht, H. J.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, I.; Wessels, J. P.; Wienold, T.; Windelband, B.; Wurm, J. P.; Xie, W.; Yurevich, S.; Yurevich, V.
Source
Pramana: Journal of Physics. May 2003 60(5):1067-1072
Subject
Language
English
ISSN
0304-4289
0973-7111
0973-7111
Abstract
The CERES/NA45 experiment at the CERN SPS has previously measurede+ e- pair production in 160 A.GeV Pb-Au collisions. In the mass regionm > 02 GeV/c2 , an enhancement of 2.7±04(stat.)±0.5(syst.) compared to the expectation from known hadronic decay sources was observed. In the 40 A.GeV data taken in 1999, an enhancement is again found; a preliminary analysis gives an even larger value of 50 ±13(stat.). The results are compared to theoretical model calculations based on π+ π- annihilation with a modified ρ-propagator; they may be related to chiral symmetry restoration.