ISSN 1330–0016 CODEN FIZBE7 PARTICLE YIELDS, ANTIPROTON SCALING AND THE AVERAGE TRANSVERSE MOMENTA IN HIGH ENERGY LEAD-LEAD COLLISIONS: A MODEL-BASED STUDY P. GUPTAROY a, 1 , S. BHATTACHARYYA b, 2 , B. DE b and D. P. BHATTACHARYYA a, 3 a Department of Theoretical Physics, Indian Association for the Cultivation of Science, Kolkata 700032, India b Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700035, India Received 11 December 2000; revised manuscript received 27 March 2001 Accepted 26 June 2001 The study aims at explaining the behaviour of some of the very important observ- ables measured in the latest lead-lead collisions at CERN in the light of a variety of the sequential chain model. Calculated values, to our surprise, are in excel- lent agreement with the measurements, especially when the effect of cascading and rescattering is empirically introduced in the calculations of the average transverse momenta. Implications of the results are discussed. PACS numbers: 25.75.-q, 13.85.Ni, 12.38.Mh UDC 539.125, 539.126 Keywords: lead-lead collisions, sequential chain model, cascading and rescattering, transverse momenta 1. Introduction Relativistic nucleus-nucleus collisions are believed to offer the unique oppor- tunity to produce and thus ‘observe’ hadronic matter at high temperatures and densities in the laboratory. In recent experiments at the CERN-SPS, a variety of reactions ranging from p+p via p+A to finally Pb+Pb collisions with controlled impact parameter and with different centralities are studied [1–3]. The ultimate 1 On leave from Department of Physics, Raghunathpur College, P.O. Raghunathpur 723133, Purulia, West Bengal,India 2 e-mail: bsubrata@www.isical.ac.in 3 e-mail: tpdpb@mahendra.iacs.res.in FIZIKA B 10 (2001) 2, 103–112 103