ENHANCED PRODUCTION OF LOW-MASS ELECTRON PAIRS IN 200-GEV NUCLEON S-AU COLLISIONS AT THE CERN SUPER PROTON SYNCHROTRON/

Authors
AGAKICHIEV G BAUR R BRESKIN A CHECHIK R DREES A JACOB C FASCHINGBAUER U FISCHER P FRAENKEL Z FUCHS C GATTI E GLASSEL P GUNZEL T HEROS CPD HESS F IRMSCHER D LENKEIT B OLSEN LH PANEBRATTSEV Y PFEIFFER A RAVINOVICH I REHAK P SCHON A SCHUKRAFT J SAMPIETRO M SHIMANSKY S SHOR A SPECHT HJ STEINER V TAPPROGGE S TELZUR G TSERRUYA I ULLRICH T WURM JP YUREVICH V
Citation
G. Agakichiev et al., ENHANCED PRODUCTION OF LOW-MASS ELECTRON PAIRS IN 200-GEV NUCLEON S-AU COLLISIONS AT THE CERN SUPER PROTON SYNCHROTRON/, Physical review letters, 75(7), 1995, pp. 1272-1275
Citations number
21
Categorie Soggetti
Physics
Journal title
Physical review letters → ACNP
ISSN journal
00319007
Volume
75
Issue
7
Year of publication
1995
Pages
1272 - 1275
Database
ISI
SICI code
0031-9007(1995)75:7<1272:EPOLEP>2.0.ZU;2-D
Abstract
We report on measurements of low-mass electron pairs in 450 GeV p-Be, p-Au, and 200 GeV/nucleon S-Au collisions at central rapidities. For t he proton induced interactions, the low-mass spectra are, within the s ystematic errors, satisfactorily explained by electron pairs from hadr on decays, whereas in the S-Au system an enhancement over the hadronic contributions by a factor of 5.0 +/- 0.7(stat) +/- 2.0(syst) in the i nvariant mass range 0.2 < m < 1.5 GeV/c(2) is observed. The properties of the excess suggest that it arises from two-pion annihilation pi pi --> e(+)e(-).