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MON: Monday Contributed Sessions

MON 10: Standard Model and Beyond

MON 10.2: Talk

Monday, September 8, 2025, 14:30–14:45, ZHG103

Quarkonia spectroscopy in the quark-gluon plasma — •Georg Wolschin — Institute for Theoretical Physics, Heidelberg, Germany

In relativistic heavy-ion collisions at RHIC and LHC energies, the spectroscopy of heavy-quarkonia states such as J/ψ and Υ(nS) that are mostly produced in the initial stages of the collision is modified through the presence of the hot plasma of gluons and light quarks. Here, we investigate the in-medium effects on the Υ and χ_b states in our theoretical Heidelberg model.

It considers, in particular, screening of the real quark-antiquark potential, collisional damping through the imaginary part of this potential, gluon-induced dissociation of the six states involved below threshold, and reduction of the feed-down contribution to the Υ(1S) spin-triplet ground state because of the screening of the higher-lying states [1]. Centrality- and transverse-momentum dependent results are compared with CMS and STAR data for the Υ(nS) states, including recent CMS results [2] for Υ(3S). The model has also been applied to Υ physics in p-Pb collisions, where the hot-medium influence can not be neglected, although cold-matter effects are dominant – as is shown in a detailed comparison with LHCb and ALICE data.

[1] G. Wolschin, Int. J. Mod. Phys. A 35, 2030016 (2020).

[2] A. Tumasyan et al. (CMS Collaboration), Phys. Rev. Lett. 133, 022302 (2024).

Keywords: Relativistic heavy-ion collisions; Quarkonia; Dissociation of bottomonia states; Model for hot-medium effects