Quark Distributions and Charged Higgs Boson Production: Studies of Proton Structure and New Physics
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
The Standard Model describes all elementary particles known today, but at larger energies it will have to be complemented with new particles and interactions. To be able to distinguish new physics at proton colliders such as LHC at CERN, it is essential to have an appropriate description of the colliding protons and their interactions. The study of the proton is important also in itself, to get a better understanding of the non-perturbative aspects of the strong interaction.
In paper I-IV of this thesis, a model for the non-perturbative dynamics of quarks and gluons is developed, based on quantum fluctuations in hadrons. The parton distributions of the proton are given by momentum fluctuations, with sea quark distributions generated by fluctuations into baryon-meson pairs. This model can reproduce proton structure function data, as well as measured asymmetries between up and down valence quark distributions and between the anti-up and anti-down sea. It provides an intrinsic charm quark component as indicated by data. It also predicts an asymmetry in the strange sea of the proton, which can explain the NuTeV anomaly first attributed to new physics beyond the Standard Model.
Charged Higgs bosons are predicted by several theories for new physics, including Supersymmetry. At proton colliders, the predicted dominant production mechanism is in association with top and bottom quarks. In paper V-VII, different contributions to this production are studied, and an algorithm is developed for combining the two dominant processes gb -> tH+/- and gg -> tbH+/-. The algorithm gives a smooth transition from small to large transverse momenta of the b-quark, which is important when the b-quark is observed. It also gives arguments for the choice of factorisation scale in the process.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 2005. , 78 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 81
Physics, quark distributions, parton density functions, proton structure, strange quark, intrinsic charm, charged Higgs boson, supersymmetry, NuTeV, LHC, parton showers, matrix element, elementary particle physics
National CategoryPhysical Sciences
IdentifiersURN: urn:nbn:se:uu:diva-5901ISBN: 91-554-6316-9OAI: oai:DiVA.org:uu-5901DiVA: diva2:166811
2005-09-23, Polhemsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Polacksbacken, Uppsala, 13:15
Zeppenfeld, Dieter, Professor
Ingelman, Gunnar, ProfessorRathsman, Johan, Docent
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