This thesis, which won one of the six 2015 ATLAS Thesis Awards, concerns the study of the charmonium and bottomonium bound heavy quark bound states. The first section of the thesis describes the observation of a candidate for the chi_b(3P) bottomonium states. This represented the first observation of a new particle at the LHC and its existence was subsequently confirmed by D0 and LHCb experiments. The second part of the thesis presents measurements of the prompt and non-prompt production of the chi_c1 and chi_c2 charmonium states in proton-proton collisions. These measurements are compared to several theoretical predictions and can be used to inform the development of theoretical models of quarkonium production.

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 polarizations within a simple model, dominated by one single color-octet production mechanism. These findings provide new insights into the dynamics of heavy quarkonium production at the LHC, an important step towards a satisfactory understanding of hadron formation within the standard model of particle physics.

This is the conference proceedings for the 18th International Conference on Hadron Spectroscopy and Structure (HADRON2019), held in Guilin, China. It is among the most important conference series in the field of hadron spectroscopy and structure. Collecting more than 130 contributions from this conference, the book spans over the topics of meson and baryon spectroscopy, exotic hadrons, hadron production and interactions, analysis tools, QCD and hadron structure, hadrons in nuclear environment and hypernuclei. Summaries of the recent discoveries from Belle, BESIII, LHCb and other high-energy experiments, as well as recent theoretical developments in the above mentioned topics, are contained in this volume, rendering it as a valuable resource for researchers working on hadron spectroscopy and structure.

Intended for graduate students, advanced undergraduates and research staff in particle physics and related disciplines and will also be of interest to physicists not working in this field who want an overview of the present development of the subject.

The book gives a quite complete and up-to-date picture of the Standard Theory with an historical perspective, with a collection of articles written by some of the protagonists of present particle physics. The theoretical developments are described together with the most up-to-date experimental tests, including the discovery of the Higgs Boson and the measurement of its mass as well as the most precise measurements of the top mass, giving the reader a complete description of our present understanding of particle physics.