Contact Information
Department of Physics525 Northwestern Avenue
West Lafayette, IN
47907-2036
Map and Directions
Telephone:
(765) 494-2970
Fax:
(765) 494-0706
Prof. Rolf P. Scharenberg - General Colloquium
November 13, 2003
Prof. Rolf P. Scharenberg
Department of Physics
Purdue University
Title: "Excitation and hadronization of deconfined hadronic matter in 
collisions at 1.8 TeV and quark-gluon to hadron phase transition"
The wide range of pseudorapidity densities 
of centrally produced hadrons from 
collisions are used to study the excitation of deconfined hadronic matter. Two signals establish the threshold for a fully connected deconfined system. First, the variation of the measured average transverse momentum of pions with 
and the color string fusion model indicate that a percolation phase transition in the initial collision occurs for 
. Secondly, the variance of the forward- backward charged particle multiplicity also exhibits a significant increase in cluster size at hadronization for 
. Above the 
threshold a one dimensional partonic expansion to the hadronization volume 4.4 
V 13.00 
has been measured. V is directly proportional to 
. Hadronization for all events above the threshold occurs at a constant energy density of 
and a constant temperature of 179.5 
5 MeV, corresponding to 24 6 quark-gluon degrees of freedom[2]. The well defined threshold signals, the partonic expansion, the constant hadronization energy density-temperature combination and the increase in the hadronic cluster size for 
, clearly indicate that deconfined hadronic matter has been excited in collisions at 1.8 TeV and subsequently hadronizes with parameters characteristic of the quark-gluon to hadron thermal phase transition.
- Charged particle multiplicity correlations in collisions at
=0.3-1.8 TeV., T. Alexopoulos, et al. (E-735 collaboration), Phys. Lett. B353 (1995) 155. - Evidence for hadronic deconfinement in collisions at 1.8 TeV., T. Alexopoulos et al. (E-735 collaboration), Phys. Lett B528 (2002) 43.