The research presented in this dissertation investigated selected processes that involve baryons and nuclei in hard scattering reactions. These processes are characterized by the production of particles with large energies and transverse momenta. Through these processes, this work explored both, the constituent (quark) structure of baryons (specifically nucleons and ∆-Isobars), and the mechanisms through which the interactions between these constituents ultimately control the selected reactions. The first of such reactions is the hard nucleon-nucleon elastic scattering, which was studied here considering the quark exchange between the nucleons to be the dominant mechanism of interaction in the constituent picture. In particular, it was found that an angular asymmetry exhibited by proton-neutron elastic scattering data is explained within this framework if a quark-diquark picture dominates the nucleon’s structure instead of a more traditional SU(6) three quarks representation. The latter yields an asymmetry around 90o center of mass scattering with a sign opposite to what is experimentally observed. The second process is the hard breakup by a photon of a nucleon-nucleon system in light nuclei. Proton-proton (pp) and proton-neutron (pn) breakup in 3He, and ∆∆-isobars production in deuteron breakup were analyzed in the hard rescattering model (HRM), which in conjunction with the quark interchange mechanism provides a QCD description of the reaction. Through the HRM, cross sections for both channels in 3He photodisintegration were computed without the need of a fitting parameter. The results presented here for pp breakup show excellent agreement with recent experimental data. In ∆∆-isobars production in deuteron breakup, the HRM angular distributions for the two ∆∆ channels were compared to the pn channel and to each other. An important prediction from this study is that the ∆++∆- channel consistently dominates ∆+∆0, which is in contrast with models that unlike the HRM consider a ∆∆ system in the initial state of the interaction. For such models both channels should have the same strength. These results are important in developing a QCD description of the atomic nucleus.

The study of the angular distribution of photon plus jet events in pp collisions at √S =7 TeV with the Compact Muon Solenoid (CMS) detector is presented. The photon is restricted to the central region of the detector (|η| < 1.4442) while the jet is allowed to be present in both central and forward regions of CMS |η| < 2.4). Dominant backgrounds due to jets fragmenting into neutral mesons are accounted for through the use of a template method that discriminates between signal and background. The angular distribution, |η*|, is defined as the absolute value of the difference in η between the leading photon and leading jet in an event divided by two. The angular distribution ranging from 0-1.4 was examined and compared with next-to-leading order QCD predictions and was found to be in good agreement.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21568号 / 理博第4475号 / 新制||理||1642(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 青木 慎也, 教授 田中 貴浩, 准教授 髙山 史宏 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23005号 / 理博第4682号 / 新制||理||1672(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 大西 明, 准教授 菅沼 秀夫, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

L’étude du processus Drell-Yan, ou la production dans des collisions entre hadrons à haute énergie d’une paire de leptons par l’intermédiaire d’un boson Z ou ɣ virtuel, est un moyen privilégié pour comprendre les mécanismes de production de particules massives comme le boson de Higgs. Dans cette thèse, les données collectées en 2016 par l’expérience CMS dans les collisions proton-proton à une énergie de 13 TeV dans le système du centre de masse, correspondant à une luminosité intégrée de 36,3 fb⁻¹, sont utilisées pour réaliser une mesure de précision de section efficaces du processus Drell-Yan différentielles en l’impulsion transverse de la paire de leptons, pour des masses invariantes de la paire allant de 50 à 1000 GeV.La mesure utilise les canaux comprenant deux électrons ou deux muons, qui ont l’avantage d’être aisément identifiables expérimentalement et, ainsi, de permettre des mesures précises de sections efficaces. Au total, environ dix millions d’événements comprenant deux électrons et vingt millions d’événements comprenant deux muons sont analysés. L’extension de l’analyse précédente de la collaboration CMS, limitée en masse invariante à l’intervalle entre 76 et 106 GeV, requiert un meilleur contrôle des bruits de fond, plus importants en-dessous de 76 et au-dessus de 106 GeV que dans l’intervalle précédemment considéré. La contribution dominante, la production d’une paire de quarks top se désintégrant en leptons, est étudiée en détail, ainsi que la contamination des données par des électrons mal identifiés. Après prise en compte de l’efficacité de détection, les résultats obtenus dans les deux canaux sont compatibles et sont combinés en une unique mesure.La précision obtenue, de l’ordre du pourcent, dans des régions jusqu’ici peu explorées permet d’obtenir de nouvelles contraintes sur des modèles largement utilisés en physique des particules. À cette fin, la mesure est comparée à six prédictions illustrant différentes approches pour la prédiction du spectre en impulsion transverse. Malgré d’assez bonnes performances générales, aucune d’entre elles ne permet une description complète des données après prise en compute des incertitudes théoriques et expérimentales. C’est en particulier le cas à grande masse invariante ou lorsqu’un jet est identifié dans l’état final. Certaines approches encore peu répandues obtiennent de meilleurs résultats dans les régions qu’elles visent spécifiquement. De nouveaux développements théoriques seront nécessaires pour combiner celles-ci afin d’obtenir des prédictions fiables dans l’ensemble de l’espace des phases. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The Large Hadron Collider is an accelerator based in the European Organization for Nuclear Research (CERN). It accelerates protons to the highest energies ever reached by the mankind. The ATLAS experiment records data from the proton-proton collisions. Common objects born in the collisions are jets, i.e. collimated bursts of hadrons. This thesis presents the newest ATLAS measurement of the inclusive jet cross-section. The data sample used was recorded in 2011 at 7 TeV centre-of-mass energy. Calorimeter is the most important part of ATLAS for the jet reconstruction. During the data taking, the hadronic calorimeter faced several failures of its components, modules. These non-operating parts have important impact on the jet energy measurement. The thesis describes tests of two available software corrections of the affected jet energies. 1

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18789号 / 理博第4047号 / 新制||理||1582(附属図書館) / 31740 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 菅沼 秀夫, 教授 國廣 悌二, 教授 田中 貴浩 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20174号 / 理博第4259号 / 新制||理||1612(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 菅沼 秀夫, 教授 國廣 悌二, 教授 川合 光 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20915号 / 理博第4367号 / 新制||理||1627(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)准教授 菅沼 秀夫, 教授 田中 貴浩, 教授 川合 光 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

Hadron structure is an important field in particle physics because hadrons make up most of the matter in nature. The theory of the strong nuclear force, via which the partons of hadrons interact, is Quantum Chromodynamics (QCD) and cannot be solved analytically. Lattice QCD (LQCD) is an ideal formulation of QCD and is the only formulation starting from first principles. In this thesis, we use LQCD for two primary topics of study: 1) nucleon structure and 2) pion and kaon structure. In the first study, we calculate the quark momentum fraction, helicity, and transversity for the nucleon. The calculations are performed on three ensembles at the physical point of the pion mass allowing us to study finite volume, discretization, strange and charm quark quenching, and excited-state systematic effects. Our calculations of the helicity and transversity are first predictions at the physical point. In the second study, we investigate pion and kaon structure. We calculate the first three non-trivial Mellin moments of the meson parton distribution functions (PDFs). For the kaon, this is the first direct calculation of the second and third moments. We carefully choose which matrix elements we implement so that there is no mixing with lower derivative operators, avoiding systematic uncertainties which are not well understood. We also perform an extensive study of the excited-state contamination. In a pioneering study, we show that the full x-dependence of the PDFs can be calculated from the first three Mellin moments. Such a calculation was previously thought to be unfeasible using moments calculated from LQCD. Our reconstruction of the PDFs allow us to comment on SU(3) flavor symmetry breaking and the high-x behavior of the pion PDF which are both interesting topics in hadron structure. / Physics