Elliptic flow of multi-strange baryons - evidence of partonic collectivity at RHIC

by Javier Castillo (Universiteit Utrecht)

Tuesday 15 Mar 2005, 14:00 → 15:00 Europe/Zurich

13/2-005 (CERN)

Lattice QCD calculations predict a transition from the deconfined thermalized partonic matter Quark Gluon Plasma (QGP) to ordinary hadronic matter at a critical temperature Tc ~170 MeV. Previous measurements of hadron yields at the intermediate and high transverse momentum and measurements of elliptic flow of hadrons indicate that a dense and strongly interacting system has been produced in Au+Au collisions at RHIC. Thus, in the early stage of the collision, dense and strongly interacting matter will yield to collective effects among constituents such as transverse collective motion (partonic collectivity). On one hand, multi-strange baryons have been suggested to be particularly sensitive to the early stage of heavy-ion collisions due to their predicted low hadronic cross sections. On the other, elliptic flow has proven to be a good tool for understanding the properties of the early stage of the collision. Therefore, elliptic flow of multi-strange baryons could be a valuable probe of the early partonic system. In this talk an overview of multi-strange baryon measurements at RHIC using the STAR detector will be presented. Particle yields give important information on the chemical properties of the system while transverse mass distributions seem to suggest multi-strange particles are insensitive to the hadronic stage of the system. Particular emphasis will be given to the measurements of elliptic flow of multi-strange baryons, which lend strong support to the idea that collective motion has developed prior to hadronization in the high-energy nuclear collisions at RHIC.



Organiser(s): Yiota Foka and Urs Achim Wiedemann