2025/02/06 by the STAR Collaboration, The STAR Collaboration
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Nuclear Experiment (nucl-ex) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2502.03769
openalex publication_date 2025/02/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report measurements of \varUpsilon(1S), \varUpsilon(2S) and \varUpsilon(3S) production in p+p collisions at √(s)=500 GeV by the STAR experiment in year 2011, corresponding to an integrated luminosity Lint=13 \mathrmpb-1. The results provide precise cross sections, transverse momentum (pT) and rapidity (y) spectra, as well as cross section ratios for pT<10 GeV/c and |y|<1. The dependence of the \varUpsilon yield on charged particle multiplicity has also been measured, offering new insights into the mechanisms of quarkonium production. The data are compared to various theoretical models: the Color Evaporation Model (CEM) accurately describes the \varUpsilon(1S) production, while the Color Glass Condensate + Non-relativistic Quantum Chromodynamics (CGC+NRQCD) model overestimates the data, particularly at low pT. Conversely, the Color Singlet Model (CSM) underestimates the rapidity dependence. These discrepancies highlight the need for further development in understanding the production dynamics of heavy quarkonia in high-energy hadronic collisions. The trend in the multiplicity dependence is consistent with CGC/Saturation and String Percolation models or \varUpsilon production happening in multiple parton interactions modeled by PYTHIA8.