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Enhanced production of low-mass electron pairs in 200 GeV/nucleon S-Au collisions at the CERN super proton synchrotron

Journal Article · · Physical Review Letters
We report on measurements of low-mass electron pairs in 450 GeV {ital p}-Be, {ital p}-Au, and 200 GeV/nucleon S-Au collisions at central rapidities. For the proton induced interactions, the low-mass spectra are, within the systematic errors, satisfactorily explained by electron pairs from hadron decays, whereas in the S-Au system an enhancement over the hadronic contributions by a factor of 5.0{plus_minus}0.7(stat){plus_minus}2.0(syst) in the invariant mass range 0.2{lt}{ital m}{lt}1.5 GeV/{ital c}{sup 2} is observed. The properties of the excess suggest that it arises from two-pion annihilation {pi}{pi}{r_arrow}{ital e}{sup +}{ital e}{sup {minus}}.
Research Organization:
Brookhaven National Laboratory
DOE Contract Number:
AC02-76CH00016
OSTI ID:
115993
Journal Information:
Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 7 Vol. 75; ISSN 0031-9007; ISSN PRLTAO
Country of Publication:
United States
Language:
English