Speaker
Description
Quarkonium production is an important probe to study the properties of the Quark Gluon Plasma (QGP) formed in relativistic heavy-ion collisions. The suppression of J/ψ due to the color-screening effect in the medium was initially proposed as direct evidence of the QGP formation. However, the interpretation of J/ψ suppression is still challenging due to the regeneration contribution from the coalescence of uncorrelated $c\bar{c}$ pairs in the medium and the cold nuclear matter effects. By comparing productions of different charmonium states in p+p, p+Au, and Au+Au collisions, the cold and hot nuclear matter effects can be systematically studied in detail.
In the 2014 and 2015 RHIC runs, the STAR experiment recorded a large amount of data in p+p, p+Au, and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV for charmonium studies via both the dielectron and dimuon channels. In this talk, we present precise measurements of nuclear modification factors for J/ψ production over a broad kinematic range in both p+Au and Au+Au collisions. We will also present the first measurements of the double ratio of ψ(2s) and J/ψ production rates at mid-rapidity in p+p and p+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. We will compare these results with model calculations and discuss physics implications of the measured cold and hot nuclear matter effects for extracting the QGP properties.
| Preferred Track | Quarkonia |
|---|---|
| Collaboration | STAR |
