| Article | |
| Title | Low-pT quarkonium polarization measurements: Challenges and opportunities |
| Related title | Low-$p_T$ quarkonium polarization measurements: Challenges and opportunities |
| Author(s) | Faccioli, Pietro (LIP, Lisbon) ; Krätschmer, Ilse (Unlisted) ; Lourenço, Carlos (CERN) |
| Publication | 2023 |
| Number of pages | 12 |
| In: | Phys. Lett. B 840 (2023) 137871 |
| DOI | 10.1016/j.physletb.2023.137871 (publication) |
| Subject category | Particle Physics - Experiment |
| Abstract | Several fixed-target experiments reported J/ψ and ϒ polarizations, as functions of Feynman x (xF) and transverse momentum (pT), in three different frames, using different combinations of beam particles, target nuclei, and collision energies. Despite the diverse and heterogeneous picture formed by these measurements, a detailed look allows us to discern qualitative physical patterns that inspire a simple empirical model. This data-driven scenario offers a good quantitative description of the J/ψ and ϒ(1S) polarizations measured in proton- and pion-nucleus collisions, in the xF≲0.5 domain: more than 80 data points (not statistically independent) are well reproduced with only one free parameter. This study sets the context for future low-pT quarkonium polarization measurements in proton- and pion-nucleus collisions, such as those to be made by the AMBER experiment, and shows that such measurements provide significant constraints on the poorly-known parton distribution functions of the pion. |
| Copyright/License | publication: © 2023-2025 The Author(s) (License: CC BY 4.0), sponsored by SCOAP³ |
Corresponding record in: Inspire
Record creato 2023-04-19, modificato l'ultima volta il 2024-02-19
