Speaker
Daniel Kikola
(Warsaw University of Technology)
Description
Suppression of quarkonia production in high energy nuclear collisions relative to proton-proton collisions, due to the Debye screening of the quark-antiquark potential, was proposed as a signature of the formation of the Quark-Gluon Plasma (QGP). Measurement of production of various quarkonia states can provide insight into thermodynamic properties of the QGP since different states have different binding energy and therefore disassociate at different temperature. However, there are other effects that may affect the observed production, such as cold nuclear matter effects, final state nuclear absorption and statistical coalescence of quark-antiquark pairs. Study of quarkonia production for different colliding systems, collision energies and centralities can help to disentangle the interplay of these mechanisms and to understand the medium properties.
In this talk we report on recent STAR results on J/psi and Upsilon production and suppression at midrapidity in Au+Au collisions at RHIC. We present J/psi invariant yield and nuclear modification factor as a function of centrality and transverse momentum at $\sqrt{s_{NN}}$ = 200, 62.4 and 39 GeV and discuss the energy dependence of the J/psi production. We also present $\Upsilon$ nuclear modification factor in Au+Au and d+Au collisions at 200 GeV calculated using high statistics p+p data taken in 2009.
Author
Daniel Kikola
(Warsaw University of Technology)
