Speaker
Description
Quarkonium production in high-energy hadronic collisions is sensitive to both perturbative and non-perturbative aspects of quantum chromodynamics (QCD) calculations. From a theoretical point of view, the production of the heavy-quark pair is described by perturbative QCD while the formation of the bound state is a non-perturbative process, treated in different ways by the available theoretical models. In this context, quarkonium polarization measurements represent a powerful tool to discriminate among the different theoretical predictions. In particular, the study of the anisotropies in the angular distribution of the decay production with respect to a given quantization axis is sensitive to the quarkonium hadronization mechanism, even if the very small values measured at the LHC have been challenging the commonly-used theoretical models. Moreover, the possibility to investigate effects related to the formation of a strongly interacting medium in ultra-relativistic heavy-ion collisions requires a precise determination of the proton-proton reference cross section and polarization. The ALICE collaboration has measured the $\Upsilon$(1S) cross section and polarization at different center-of-mass energies and in this contribution we will present the recent measurements in pp collisions at $\sqrt{s}=$ 13 TeV at forward rapidity (2.5 < y < 4) in the dimuon channel. In addition, thanks to the upgraded detector and the large data sample collected in LHC Run 3 the preliminary measurement of $\Upsilon$(2S)-to-$\Upsilon$(1S) ratio both at mid ( |y| < 0.9) and forward rapidity (2.5 < y < 4) will be presented for the first time at $\sqrt{s}=$ 13.6 TeV in the $e^{+}e^{-}$ and $\mu^{+}\mu^{-}$ decay channel respectively.
| Category | Experiment |
|---|---|
| Collaboration (if applicable) | ALICE |
