Systematic study of low-mass electron pair production in p-Be and p-Au collisions at 450 GeV/c
- ] G.Agakichiev
- M. Appenheimer
- R. Averbeck
- R. Baur
- A. Brenschede
- J. Diaz
- A. Drees
- U. Faschingbauer
- J.L. Ferrero
- P.Fischer
- Z. Fraenkel
- M. Franke
- Ch. Fuchs
- E. Gatti
- P. Glässel
- Th. Günzel
- C. P. de los Heros
- F. Hess
- R. Holzmann
- V.Iourevitch
- D. Irmscher
- C. Jacob
- W. Kühn
- B. Lenkeit
- H. Löhner
- A. Marin
- F.M. Marques
- G. Martinez
- V. Metag
- M.Notheisen
- R. Novotny
- L. H. Olsen
- R. Ostendorf
- Y. Panebrattsev
- A. Pfeiffer
- I. Ravinovich
- P. Rehak
- M. Sampietro
- A.Schön
- J. Schukraft
- Y. Schutz
- S. Shimansky
- A. Shor
- R.S. Simon
- H.J. Specht
- V. Steiner
- S. Tapprogge
- G. Tel-Zur
- I. Tserruya
- Th. Ullrich
- H. Wilschut
- J. P. Wurm
DOIAbstract
In a joint effort the CERES/NA45 and TAPS collaborations have measured low-mass electron pairs in p Be and p Au collisions at 450 GeV/c at the CERN SPS. In the range covered up to ≈ 1.5 GeV/c^2 the mass spectra from p Be and p Au collisions are well explained by electron pairs from decays of neutral mesons. For p Au our result is new. For p Be, the simultaneously measured electron pair inclusive pair spectrum in which instrumental uncertainties are highly reduced. We confirm the earlier finding of HELIOS-1 with significantly reduced systematic uncertainties of 23% in the mass range below 450 MeV/c^2, and of 28% in the mass range above 750 MeV/c^2 at 90% confidence limit. Any unconventional source of electron pairs is limited by these error ...