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Description
9:00- 9:15 Urs.Wiedemann
9:15-10:15 Sergey Panitkin
10:15-10:45 coffee break
10:45-11:15 Laurent Rosselet
11:15-12:00 Ulrich Heinz
12:00-12:30 Jan Pluta
12:30-13:30 lunch
Afternoon, bldg 60-6-002
13:30-14:00 Richard Lednicky
14:00-14:30 Yury Sinyukov
Introduction
by Urs Wiedemann (CERN)
Meson Correlations in Au+Au collisions at sqrt_s=130 GeV
by Sergey Panitkin (BNL)
Measurements of two-particle correlations can provide an important information about space-time evolution of the system created in heavy
ion collisions. They also provide stringent constraints for theoretical
models. Preliminary results of the meson correlations analysis performed by the STAR Collaboration at RHIC will be presented.
Paper available: K.H. Ackermann et al, STAR Collaboration, nucl-ex/0009011, 2000.
Three-pion interferometry from the WA98 experiment in central 158 AGeV Pb+Pb collisions
by Laurent Rosselet (Univ. of Geneva)
Compared to two-particle interferometry, three-particle interferometry can provide additional information on the space-time emission. In particular, if the emission is fully chaotic, the three-particle interference study gives access to the phase of the source function's Fourier transform, which is affected by the emission asymmetry. Three-particle correlations have been measured for identified negative pions from central 158 A GeV Pb+Pb collisions by the WA98 experiment. A substantial contribution of the genuine three-body correlation has been found, which is compatible with a mainly chaotic and symmetric source.
Multi-Boson Effects in Bose-Einstein Interferometry
by Ulrich Heinz (CERN)
Multi-boson symmetrization effects are expected to affect single-particle momentum spectra and 2-particle correlations if, at freeze-out, the boson phase space density is large. In event ensembles with arbitrary multiplicity distributions they also lead in general to new residual correlations which modify the shape of the 2-boson correlation function. It is argued that this shape change does not depend on details of the source and is controlled predominantly by its average phase-space density. It can thus be used to search for (the absence of) multi-boson effects. Various other aspects related to this shape change are also discussed: variations in the apparent correlation strength ('intercept parameter'), the general absence of phase coherence in models with independent particle emission ('chaotic sources'), and the impossibility of obtaining a 'pion laser' in such models.
A program of close velocity correlation studies for ALICE
Jan Pluta (Warsaw University of Technology)
In the frame of Physics Performance Report for ALICE a program for 'Space-time evolution; momentum correlations' is proposed. The contents of this program will be shortly reviewed and discussed. The main points will include: present situation, HBT corrrelations for expanding systems, role of HBT correlations in interpreting QGP signatures, specific effects of correlations at LHC energies, event generation with specific afterburners, correlation effects for ALICE geometry and resolution, conclusions for ALICE hardware and software development. The plan for realisation of this program will be briefly discussed as well.
Recent NA49 results on unlike particle correlations in Pb+Pb collisions at 160 AGeV
by Richard Lednicky (Institute of Physics, Prague and MPI, Munich)
Recent NA49 results on unlike particle correlations at small relative velocities are presented based on 400k events of central Pb+Pb collisions at 158 AGeV. Comparison with the RQMD transport code simulations indicates 20 per cent overestimation of the space-time freezeout characteristics in the model.
The relative space-time asymmetries between pions and protons are observed on the level of several per cent. They agree with the RQMD predictions and also, qualitatively, with the predictions based on a universal hydrodynamical transversal flow parametrized in the usual linear form which, however, seems to underestimate the size of the effect. Being sensitive to the relative time delays and to the intensity of collective flows, the correlations of unlike particles can become a promising tool in a study of the deconfinement transition and the formation of quark-gluon plasma.
Correlation search for coherent pion emission in heavy ion collisions
by Yuri Sinyukov (Bogolyubov ITP, Kiev and Subatech, Nantes)
The methods allowing to extract the coherent pion spectrum from Pi-Pi-, Pi+Pi+ and Pi+Pi- correlation functions and single-pion spectra are suggested. They exploit a nontrivial modification of the quantum statistical and final state interaction effects on the correlation functions of like and unlike pions in the presence of charge-constrained coherent states. The possible physical processes which could produce the coherent pion radiation in ultra-relativistic nuclear collisions are discussed.
In collaboration with S.Akkelin and R.Lednicky
Organiser(s): Yiota Foka, Ulrich Heinz and Urs Wiedemann
Organiser(s): Yiota Foka, Ulrich Heinz and Urs Wiedemann