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Abstract
Abstract.
Two-particle correlations of negative pions as a function of charged particle multiplicity are studied in Pb+Pb collisions at \(\sqrt{s}=17.3\)GeV per nucleon using the NA44 experiment at the CERN Super Proton Synchrotron(SPS). We find that the source size parameters increase with the charged particle multiplicity. However the slope of the source size parameters plotted as a function of charged multiplicity is slightly larger at high multiplicity than at low multiplicity. The value of \(\lambda\) is independent of charged multiplicity. For Pb+Pb collisions, \(R_L\) is larger than \(R_{TS}\) and \(R_{TO}\) for all multiplicity intervals, whereas these three radius parameters were approximately equal in S+Nucleus collisions. The ratios (\(R_L/R_{TS}\)) and (\(R_L/R_{TO}\)) for Pb+Pb data show almost no dependence on charged multiplicity. The duration of pion emission \(\Delta \tau\) is constant at 3.8\(\pm\)1.1 fm/c as a function of the charged multiplicity in Pb+Pb collisions. Effective volume (V) is also calculated as V=\(\pi\times R_{TS}^2\times R_L\), assuming a cylindrically shaped source. We found, within the limited statistics, the effective volume rapidly increases at high multiplicity.
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1 Niels Bohr Institute, 2100 Copenhagen, Denmark , DK
2 Los Alamos National Laboratory, Los Alamos, NM 87545, USA , US
3 Nuclear Physics Laboratory of Nantes, 44072 Nantes, France , FR
4 Department of Physics, Columbia University, New York, NY 10027,USA , US
5 Hiroshima University, Higashi-Hiroshima 739-8526, Japan , JP
6 CERN, 1211 Geneva 23, Switzerland , CH
7 Rudjer Bošković Institute, Zagreb, Croatia , HR
8 Department of Physics, The Ohio State University, Columbus, OH 43210, USA , US
9 State University of New York, Stony Brook, NY 11973, USA , US
10 Department of Physics, University of Lund, 22362 Lund, Sweden , SE
11 Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA , US
12 Brookhaven National Laboratory, Upton, NY 11973, USA , US