The electroweak standard model, as well-known, has been remarkably successful in describing a broad spectrum of high energy physics and has also given a satisfactory and consistent theoretical description of all the experimental data which has been obtained so far. The aim of the present work is to investigate some of the most important processes associated with the standard model which involve the charged intermediate bosons W(^±), the neutral intermediate boson Z, the pair production of weak gauge bosons and the Higgs boson. First of all we start with the study of the effect of the strong interaction on the direct production of weak gauge boson production at hadron colliders. We calculate the first order perturbative QCD corrections O(a(_s)) to the lowest order cross sections for photon and Z pair production at hadron colliders. The calculation contains divergences, represented in dimensional regularisation by poles of order O(1/ϵ) and O(1/ϵ(^2)), where ϵ = 4-n(_2). The order O(1/ϵ(^2)) terms are eliminated when real and virtual corrections are combined, and the remaining 0(1/ϵ) corrections will be absorbed into the quark momentum distribution functions. We then study the production rate of weak gauge boson pairs for proton- proton and proton-antiproton colliders using single and double parton scattering mechanisms. We extrapolate to the next generation of hadron colliders with centre-of-mass energy E(_cm)= 10-200 TeV. We find comparable values for the single and double scattering cross sections at very high energies. To expand our investigation, we study also the production rate of multiple gauge bosons at hadron supercolliders using the double parton scattering mechanism. These kinds of processes are important and represent a potential significant background for Higgs boson production. Finally, and for completeness, we study Higgs boson phenomenology, which now forms a substantial part of the physics program at the next generation of high-energy colliders. The calculation covers the production rate of single and double Higgs production at hadron colliders via gluon-gluon fusion, their branching ratios and decay widths.

Submitted by ANDRES FELIPE VASQUEZ TOCORA (anfvasquezto@unal.edu.co) on 2018-10-02T21:56:33Z No. of bitstreams: 1 thesis.pdf: 3832471 bytes, checksum: 13b65d2c4a9d5e2b2c7414dd2cdfba50 (MD5) / Rejected by Hellen Sayuri Sato null (hellen@ift.unesp.br), reason: Solicitamos que realize correções na submissão seguindo as orientações abaixo - Favor inserir a ficha catalográfica no pdf , logo após a página de rosto - No PDF está faltando as palavras-chave logo após o resumo e abstract on 2018-10-03T14:34:04Z (GMT) / Submitted by ANDRES FELIPE VASQUEZ TOCORA (anfvasquezto@unal.edu.co) on 2018-10-03T16:52:45Z No. of bitstreams: 1 Thesis.pdf: 4205198 bytes, checksum: 499748f6d69605fda811e56805ac4e12 (MD5) / Approved for entry into archive by Hellen Sayuri Sato null (hellen@ift.unesp.br) on 2018-10-03T17:32:51Z (GMT) No. of bitstreams: 1 vasqueztocora_af_me_ift.pdf: 4205198 bytes, checksum: 499748f6d69605fda811e56805ac4e12 (MD5) / Made available in DSpace on 2018-10-03T17:32:51Z (GMT). No. of bitstreams: 1 vasqueztocora_af_me_ift.pdf: 4205198 bytes, checksum: 499748f6d69605fda811e56805ac4e12 (MD5) Previous issue date: 2018-03-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The main goal of this dissertation is to show the enhancement of the cross-section for the double Higgs production through pair annihilation by including effective interactions and through the non-perturbative Sommerfeld effect. Bounds to some Wilson coefficients were obtained from such enhancement, this in the scenarios of the future e+ e− -colliders (FCC-ee, ILC, CLIC). In order to achieve this, some computational tools were implemented: FeynRules, FeynArts, FormCalc, and LoopTools. It is also shown the enhancement of the double Higgs production in 2HDM and MSSM, discussing the general framework of these two models. In addition, it is studied the threshold behavior of the cross-section for the double Higgs production when a hidden sector couples to the Higgs boson, yielding resonances below the threshold energy due to non-perturbative effects. We study the Sommerfeld effect in the double Higgs production in the scenario of e+ e− -colliders. The enhancement is discussed as generated from a hidden sector coupled to the Higgs boson. Below and above threshold enhancements are presented. Such analysis is of importance in the ILC project, which will operate up to the threshold energy √s = 250 GeV. The results has been achieved by the use of computational tools like FeynArts, FormCalc, and LoopTools. / O objetivo principal dessa dissertação é, mostrar o aprimoramento da seção de choque para a produção em dobro dos bósons de Higgs, por meio de aniquilação de pares, incluindo interações efetivas e através do efeito não perturbativo de Sommerfeld. De tais aprimoramentos, os limites para alguns coeficientes de Wilson foram obtidos, isso nos cenários de futuros aceleradores de e+e- (FCC-ee, ILC, CLIC). Para atingir estes resultados, algumas ferramentas computacionais foram implementadas: FeynRules, FeynArts, FormCalc e LoopTools. Também, é mostrado o aprimoramento da produção em dobro de bósons de Higgs no “2HDM” e “MSSM”, discutindo o marco geral desses dois modelos. Além disso, foi estudado o comportamento, perto do limite de produção, da seção de choque da produção em dobro dos bósons de Higgs, quando um setor escondido é acoplado ao Higgs, produzindo ressonâncias abaixo da energia limite de produção, devido à efeitos não perturbativos.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第22999号 / 理博第4676号 / 新制||理||1671(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) 長野 邦浩, 教授 中家 剛, 准教授 吉岡 興一 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM