First results from CERES/NA45 on low-mass electron pair production in PbAu collisions

✍ Scribed by Th. Ullrich; G. Agakichiev; R. Baur; P. Braun-Munzinger; F. Ceretto; A. Drees; S. Esumi; U. Faschingbauer; Ch. Fuchs; E. Gatti; P. Glässel; C.P. de los Heros; P. Holl; Ch. Jung; H. Kraner; B. Lenkeit; M. Messer; Y. Minaev; Y. Panebrattsev; A. Pfeiffer; J. Rak; I. Ravinovich; S. Razin; P. Rehak; M. Sampietro; J. Schukraft; S. Shimanskiy; E. Socol; H.J. Specht; J. Stachel; G. Tel-Zur; I. Tserruya; Th. Ullrich; C. Voigt; C. Weber; J.P. Wessels; J.P. Wurm; V. Yurevich

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 902 KB
• Volume: 610
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(96)00366-1

✦ Synopsis

We report preliminary results of the first measurement of low-mass electron pairs in 160 GeV/nucleon Pb-Au collisions at central rapidities in a wide multiplicity range. This work is the continuation of our systematic studies on pair production in p-Be, p-Au and S-Au interactions. The motivation for this effort derives from a new source of lowmass dileptons recently observed in S-Au and S-W collisions by CERES and HELIOS/3, respectively. The results obtained in the analysis of the Pb-Au data confirm our previous finding that pair production in the mass range 0.2 < m~e < 1.5 GeV/c 2 is enhanced over the contributions from hadron decays while no significant excess could be observed for mee < 2m~. A comparison of the results for different multiplicity bins favours a non-linear dependence of the e+e--yield on the accompanying charged particle densities.