Search for ”hidden charm” in relativistic collisions of heavy ions

aim of project
The scientifi c aim of the project is the study of production of particles of hidden charm, i.e. mesons J/ψ, using available (and continuously collected) data from RHIC accelerator at Brookhaven National Laboratory, BNL (USA) and on the basis of this, gaining new information on phase change into gluon-quark plasma in relativistic collisions of heavy ions. The project is conducted in the Laboratory of Heavy Ions Reactions at the Faculty of Physics of Warsaw University of Technology within the STAR experiment, currently realized at BNL. Main emphasis in data analysis is put on systematic study of cross-section and various aspects of spectra of lateral momenta. Separating dissociation and regeneration scripts of J/ψ requires a full description both in the function of lateral momentum and centrality of interaction, which in turn requires provision of immense statistics during future exposure on RHIC. Moreover, in order to determine whether J/ψ damping is connected with formation of plasma at earlier stages of A+A infl uence, one should analyze production of J/ψ in reactions in which à priori plasma cannot occur, e.g. p+p or p+A at the same energy (and ideally — in the same experimental conditions). The experimental program for RHIC contains all critical directions of study of J/ψ production: p+p, p+A and A+A. Research is conducted in cooperation with foreign centers, especially with a group from Lawrence Berkeley National Laboratory (LBNL).

expected results
Results of the conducted tasks will be published in reviewed scientific journals and will be presented at international conferences. The collected experimental materials will be the basis of Ph.D. dissertations at the WUT Faculty of Physics, they will also be part of a habilitation dissertation of one of the participants of the project. Parts of papers accompanying the project will also be used in diploma theses written by students of the WUT Faculty of Physics. A crucial result of the realization of the program will be preparation of procedures and skills for continuation of research on LHC energies at CERN within the ALICE experiment, prepared there. Contribution of “hard” processes at LHC energies will be dominant, therefore both having information on lower energies (RHIC) and ability to analyze data, and having operating and proven software will be valuable for the continuation of research. The Laboratory of Heavy Ions Reactions at the WUT Faculty of Physics is a member of the ALICE experiment and the measurement system of that experiment has many elements analogical to the STAR experiment.