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Title: Intriguing centrality dependence of the Au-Au source size at the AGS

One of the main goals of high energy heavy ion physics is to establish the existence of a deconfined phase of nuclear matter--the quark-gluon plasma--at high temperatures or densities. One possible signature of such a phase transition, especially if it were first order, would be a larger source size or lifetime than a similar hadronic system. At current AGS energies, we attempt to form a quark- gluon plasma by achieving a high baryon density for a period of time in the center of the collision region. For a given density threshold, the size of this high density region should be a strong function of the impact parameter: the more central the event, the larger the high density region. Therefore, one possible signature of a quark-gluon plasma would be a sudden change in system lifetime or size as a function of the centrality of the collision. In this talk we present an intriguing effect which was not predicted for simple hadronic systems: a rapid increase of the HBT-measured source radius parameter for pion pairs with increasing centrality for Au-Au collisions at a beam momentum of 11.45 A GeV/c on a fixed target. Experience has shown, however, that we must be cautiousmore » in our interpretation. A complete understanding of the collision dynamics at a given energy must be built up from several measurements and new, but conventional, hadronic explanations must be considered for such unexpected effects. More study is needed, therefore, before any strong conclusions can be reached.« less
Authors:
 [1] ;
  1. Massachusetts Inst. of Tech., Cambridge, MA (United States)
Publication Date:
OSTI Identifier:
249214
Report Number(s):
BNL-63059; CONF-960294-1
ON: DE96011503; TRN: 96:015995
DOE Contract Number:
AC02-76CH00016
Resource Type:
Conference
Resource Relation:
Conference: 12. winter workshop on nuclear dynamics, Snowbird, UT (United States), 3-10 Feb 1996; Other Information: PBD: [1996]
Research Org:
Brookhaven National Lab., Upton, NY (United States)
Sponsoring Org:
USDOE, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States); US-Japan High Energy Physics Collaboration
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; GOLD 197 TARGET; GOLD 197 REACTIONS; QUARK MATTER; PARTICLE PRODUCTION; ATOM-ATOM COLLISIONS; QUARK-GLUON INTERACTIONS; PIONS MINUS; GOLD 197 BEAMS; PION-PION INTERACTIONS