Measurement of Quarkonium Polarization to Probe QCD at the LHC

This thesis discusses in detail the measurement of the polarizations of all S-wave vector quarkonium states in LHC proton-proton collisions with the CMS detector. Heavy quarkonium states constitute an ideal laboratory to study non-perturbative effects of quantum chromodynamics and to understand how quarks bind into hadrons.
The experimental results are interpreted through an original phenomenological approach, which leads to a coherent picture of quarkonium production cross sections and pola...