Quarkonium polarisation studies in p+p collisions

The mechanism of quarkonium production in hadronic collisions remains an open question. Despite numerous measurements at RHIC and the LHC, none of the existing models can consistently describe both the measured production cross-section and the polarization across the full kinematic range. This calls for new, high-precision differential measurements.
The proposed research will leverage the large data sample of p+p collisions at the centre-of-mass energy of 510 collected by the STAR experiment at RHIC during the 2022 run.
This extensive dataset will provide the statistical power necessary to perform the first-ever measurement of the Upsilon polarization at RHIC, providing a crucial test of Non-Relativistic Quantum Chromodynamics (NRQCD) predictions. The data will also enable novel correlation studies, specifically exploring correlation between mid-rapidity Upsilon polarization and jet or hadron production at forward rapidity, made possible by the 2022 STAR Forward Upgrade, which allows detailed probing of the initial-state partonic dynamics.
These studies will be complemented by feasibility analyses of quarkonium production measurements with the ePIC experiment at the future Electron-Ion Collider (EIC), establishing an important connection between current and forthcoming facilities. This work will help bridge the understanding of quarkonium production mechanisms from hadronic to electron-ion collisions. Furthermore, the methodologies and analysis techniques developed within this project will directly inform future quarkonium production, polarization and correlation studies at the EIC.