Speaker
Description
In ultra-relativistic heavy-ion collisions, creation of a novel state of matter, the quark-gluon plasma (QGP), has been observed. This hot, dense, and short-lived medium of deconfined quarks and gluons is experimentally very challenging to study. Suppressed production of heavy quarkonia, caused by colour screening of the binding force, has been viewed as a direct evidence of the QGP formation. Moreover, different quarkonium states are expected to dissociate at different temperatures, which can be used to constrain the properties of the medium.
In this poster, we will present recent measurements of the $\Upsilon$ production in Au+Au collisions at $\sqrt{s_\mathrm{NN}}=200$ GeV via the di-lepton channel by the STAR experiment at RHIC. At RHIC energies, other phenomena influencing the quarkonium production, such as the regeneration and co-mover absorption, are expected to have little or no effect for the bottomonium family, which makes it a cleaner probe compared to the $J/\psi$ meson. We will show the nuclear modification factors for both the ground and excited $\Upsilon$ states. Furthermore, we will compare these with results from p+Au collisions at RHIC, which provide a quantification of the cold nuclear matter effects, and also with measurements from Pb+Pb collisions at the LHC as well as with theoretical calculations.
| Content type | Experiment |
|---|---|
| Collaboration | STAR |
| Centralised submission by Collaboration | Presenter name already specified |
