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Étalonnage du calorimètre électromagnétique d'ATLAS recherche du boson de Higgs dans ses désintégrations invisibles /Neukermans, Lionel Colas, Jacques. January 2002 (has links) (PDF)
Reproduction de : Thèse de doctorat : Physique nucléaire : Lyon 1 : 2002. / Titre provenant de l'écran titre. 85 réf. bibliogr.

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Signals of nonminimal Higgs sectors at future collidersAkeroyd, Andrew Gerard January 1996 (has links)
This thesis concerns the study of extended Higgs sectors at future colliders. Such studies are well motivated since enlarged Higgs models are a necessity in many extensions of the Standard Model (SM), although these structures may be considered purely in the context of the SM, to be called the 'nonminimal SM'. The continuous theme of the thesis is the task of distinguishing between the (many) theoretically sound nonminimal Higgs sectors at forthcoming colliders. If a Higgs boson is found it is imperative to know from which model it originates. In particular, the possible differences between the Higgs sectors of the Minimal Supersymmetric Standard Model (MSSM) and the nonminimal SM are highlighted. Considered first are the detection prospects of light charged Higgs scalars (H(^±)) at e(^+)e(^) colliders. The discovery of a H(^±) would provide unambiguous evidence for a non minimal Higgs sector. We show that in certain (but not all)nonminimal models a light H(^±) may exist i.e. be within the mass range accessible at LEP2 (M(_H)(_ ±) ≤ Mw). In particular the MSSM requires M(_H±) ≥ Mw, and thus detection of a at LEP2 is strong evidence against the MSSM. We discuss ways of distinguishing between the models which may contain a light H(^±) by exploiting differences in the decay channels. Attention is then given to the neutral Higgs bosons of the nonminimal SM. It is possible that these particles may possess a greatly different phenomenology to that of the mammal SM and MSSM, and we explore the feasibility of observing these differences at LEP2 and the LHC It is found that distinct, sometimes spectacular signatures are possible. The thesis next considers a more exotic Higgs representation, namely that of Higgs triplets, and compares its phenomenology at LEP2 with that of the nonminimal models covered thus far The phenomenon of Higgs bosons decoupling from the fermions(fermiophobia) arises naturally in the above triplet model, and this concept is studied in more depth in the final chapter. It is emphasized that such particles are not possible in the MSSM.

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Low energy consequences of some nonstandard Higgs modelsThompson, David Ian. January 2007 (has links)
Thesis (Ph.D.)  University of Glasgow, 2007. / Ph.D. thesis submitted to the Department of Physics and Astronomy, Faculty of Physical Sciences, University of Glasgow, 2007. Includes bibliographical references. Print version also available.

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Srch for charged Higgs bosons decaying to top and bottom quarks in protonantiproton collisionsKertzscher, Gustavo, January 1900 (has links)
Thesis (M.Sc.). / Written for the Dept. of Physics. Title from title page of PDF (viewed 2009/06/25). Includes bibliographical references.

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A search for Higgs bosons in final states with multiple tau leptons at the DZero experimentSuter, Louise January 2013 (has links)
Two searches for the production of Higgs bosons decaying into tau and mu leptons, using data collected with the DZero detector at the Fermilab Tevatron pbar(p)collider, are presented. A search for the pair production of doubly charged Higgs bosons in the processqbar(q) to H^{++}H^{}, where H^{++} decays to tautau, mumu or taumu lepton pairs, with an integrated luminosity of up to L= 7.0 fb^{1}, is presented. No significant excess of data over the expected SM background is observed and the results are used to set 95\% C.L. limits on the pair production cross section of doubly charged Higgs bosons in the range 90 < M_{H^{++}} < 200 GeV. A second search for the production of the Standard Model Higgs boson in the final state tautaumu+X is presented, using an integrated luminosity of L=8.6 fb^{1}. Again no significant excess of data is observed over the background expectation and 95% C.L. limits are set on the observed cross section relative to the Standard Model prediction, in the range 100 < M_{H} < 200 GeV.

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Prototyping for the central detector and CPviolation studies with the CMS experimentVite, Davide Francesco January 1996 (has links)
No description available.

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Higgs and Particle Production in NucleusNucleus CollisionsLiu, Zhe January 2015 (has links)
We apply a diagrammatic approach to study Higgs boson, a colorneutral heavy particle, production in nucleusnucleus collisions in the saturation framework without quantum evolution. We assume the strong coupling constant much smaller than one. Due to the heavy mass and colorless nature of Higgs particle, final state interactions are absent in our calculation. In order to treat the two nuclei dynamically symmetric, we use the Coulomb gauge which gives the appropriate light cone gauge for each nucleus. To further eliminate initial state interactions we choose specific prescriptions in the light cone propagators. We start the calculation from only two nucleons in each nucleus and then demonstrate how to generalize the calculation to higher orders diagrammatically. We simplify the diagrams by the SlavnovTaylorWard identities. The resulting cross section is factorized into a product of two WeizsäckerWilliams gluon distributions of the two nuclei when the transverse momentum of the produced scalar particle is around the saturation momentum. To our knowledge this is the first process where an exact analytic formula has been formed for a physical process, involving momenta on the order of the saturation momentum, in nucleusnucleus collisions in the quasiclassical approximation. Since we have performed the calculation in an unconventional gauge choice, we further confirm our results in Feynman gauge where the WeizsäckerWilliams gluon distribution is interpreted as a transverse momentum broadening of a hard gluons traversing a nuclear medium. The transverse momentum factorization manifests itself in light cone gauge but not so clearly in Feynman gauge. In saturation physics there are two different unintegrated gluon distributions usually encountered in the literature: the WeizsäckerWilliams gluon distribution and the dipole gluon distribution. The first gluon distribution is constructed by solving classical YangMills equation of motion in the McLerranVenugopalan model, while the second gluon distribution is related to the dipole scattering amplitude. So far, the quantum structure of the dipole gluon distribution has not been thoroughly investigated. Applying the same diagrammatic techniques, we carry out a detail study of the quantum structure of the color dipole gluon distribution, and then compare it with that of the WeizsäckerWilliams gluon distribution.

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Detection Prospects of Doubly Charged Higgs Bosons from the Higgs Triplet Model at the LHCLindahl, Viveca January 2011 (has links)
In this thesis I explore the possibilities of detecting doubly charged Higgs bosons from the Higgs Triplet Model (HTM) at the Large Hadron Collider (LHC) at CERN. Higgs bosons are included into the Standard Model (SM) of particle physics in order to explain the origin of mass of the elementary particles. Even though the SM is considered to be a reliable starting point for any particle theory, no Higgs particles have to this day been found. There are therefore high expectations for the recordbreaking energies of the LHC to lead to a Higgs discovery. The HTM produces seven different Higgs bosons, and among these we find the doubly charged ones. Because of their exotic charge, I focus on studying these Higgs particles in particular. To this purpose, I implement the full HTM theory as an alternative model option in standard particle physics MonteCarlo software and then simulate LHC protonproton collisions at a center of mass energy of 14 TeV. The investigated signal is defined as two likesigned leptons, four hard jets and missing energy in the final state. The main production mechanisms are pairproduction and associated production with a singly charged Higgs. Since I choose to study a region of parameter space where the triplet vacuum expectation value is relatively large, the doubly charged Higgs decays into W's and the singly charged Higgs into WZ or tb. The results of the simulations show that the LHC could probe Higgs masses up to at least 300 GeV with an integrated luminosity of about 300 fb.1.

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Étude du calorimètre électromagnétique de l'expérience CMS et recherche de bosons de Higgs neutres dans le canal de production associéeRavat, Olivier El Mamouni, Houmani January 2004 (has links) (PDF)
Reproduction de : Thèse de doctorat : Physique des particules : Lyon 1 : 2004. / Titre provenant de l'écran titre. 103 réf. bibliogr.

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Mesure de la section efficace de production de paires de quarks top dans l'expérience CMS au LHCAndrea, Jérémy Bloch, Daniel. January 2009 (has links) (PDF)
Thèse de doctorat : Physique des particules : Strasbourg : 2009. / Titre provenant de l'écrantitre. Bibliogr. 7 p.

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