2020 Impact factor 4.590
Particles and Fields
Eur. Phys. J. C 18, 317-325
DOI 10.1007/s100520000543

Space-time evolution of the hadronic source
in peripheral to central Pb+Pb collisions

I.G. Bearden1 - H. Bøggild1 - J. Boissevain2 - P.H.L. Christiansen1 - L. Conin4 - J. Dodd3 - B. Erazmus4 - S. Esumi5 - C.W. Fabjan6 - D. Ferenc7 - A. Franz6 - J.J. Gaardhøje1 - A.G. Hansen1 - O. Hansen1 - D. Hardtke9 - H. van Hecke2 - E.B. Holzer6 - T.J. Humanic9 - P. Hummel6 - B.V. Jacak10 - K. Kaimi5 - M. Kaneta $^{5,\rm e}$ - T. Kohama5 - M. Kopytine10 - M. Leltchouk3 - A. Ljubicic Jr. $^{7,\rm c}$ - B. Lörstad11 - N. Maeda5 - L. Martin4 - A. Medvedev3 - M. Murray8 - H. Ohnishi $^{5,\rm c}$ - G. Paic6,9 - S.U. Pandey9 - F. Piuz6 - J. Pluta4 - V. Polychronakos12 - M. Potekhin3 - G. Poulard6 - D. Reichhold9 - A. Sakaguchi5 - J. Schmidt-Sørensen11 - J. Simon-Gillo2 - W. Sondheim2 - T. Sugitate5 - J.P. Sullivan2 - Y. Sumi5 - W.J. Willis3 - K. Wolf $^{8,\rm f}$ - N. Xu $^{2,\rm e}$ - D.S. Zachary9

1 Niels Bohr Institute, 2100 Copenhagen, Denmark
2 Los Alamos National Laboratory, Los Alamos, NM 87545, USA
3 Department of Physics, Columbia University, New York, NY 10027,USA
4 Nuclear Physics Laboratory of Nantes, 44072 Nantes, France
5 Hiroshima University, Higashi-Hiroshima 739-8526, Japan
6 CERN, 1211 Geneva 23, Switzerland
7 Rudjer Boskovic Institute, Zagreb, Croatia
8 Cyclotron Institute, Texas A&M University, College Station, TX 77843, USA
9 Department of Physics, The Ohio State University, Columbus, OH 43210, USA
10 State University of New York, Stony Brook, NY 11973, USA
11 Department of Physics, University of Lund, 22362 Lund, Sweden
12 Brookhaven National Laboratory, Upton, NY 11973, USA

Received: 17 July 2000 / Revised version: 3 November 2000 /
Published online: 8 December 2000 - © Springer-Verlag 2000

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, RL is larger than RTS and RTO for all multiplicity intervals, whereas these three radius parameters were approximately equal in S+Nucleus collisions. The ratios ( RL/RTS) and ( RL/RTO) 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.

Copyright Società Italiana di Fisica, Springer-Verlag 2000