Дисертації з теми "Fermion masse"
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BELFATTO, BENEDETTA. "Flavour problems and new physics at TeV scale." Doctoral thesis, Gran Sasso Science Institute, 2020. http://hdl.handle.net/20.500.12571/10042.
Повний текст джерелаLucente, Michele. "Implication of Sterile Fermions in Particle Physics and Cosmology." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112210/document.
Повний текст джерелаThe neutrino mass generation mechanism, the nature of dark matter and the origin of the baryon asymmetry of the Universe are three compelling questions that cannot be accounted for in the Standard Model of particle physics. In this thesis we focus on all these issues by providing a possible solution in terms of a minimal extension of the Standard Model, consisting in the addition of a set of sterile fermions to the field content of the theory. Sterile fermions are gauge singlet fields, that can interact via mixing with the active neutrinos. We focus on the Inverse Seesaw mechanism, which is characterised by a low (TeV or lower) new physics scale and that can be tested in current and future experimental facilities. We present the model building analysis that points towards the minimal realisations of the mechanism, and the phenomenological study in order to accommodate light neutrino masses and to impose all the relevant experimental constraints in the model, as well as the expected experimental signatures. We show the viability of the sterile neutrino hypothesis as dark matter component, together with the characteristic features of this scenario in the minimal Inverse Seesaw mechanism. The possibility of successfully accounting for the baryon asymmetry in a testable realisation of the leptogenesis mechanism is also addressed.On the other side it is important to look for manifestations of sterile fermions in laboratory experiments. We address this point by making predictions for the expected rates of rare lepton number violating decays of vector bosons, that can be mediated by sterile fermions, as well as by studying the impact of sterile fermions on global fit of electroweak precision data
Özer, Alp Deniz. "SO(10)-Grand Unification and Fermion Masses." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-46957.
Повний текст джерелаBloch, Jacques Christophe Rodolphe. "Numerical investigation of fermion mass generation in QED." Thesis, Durham University, 1995. http://etheses.dur.ac.uk/5173/.
Повний текст джерелаBhatti, Abdul Aziz. "Fermion masses and Higgs Physics in Grand Unified Theories." Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-114132.
Повний текст джерелаTherrien, Eric. "Fermion masses and mixing in a simple composite model." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63874.
Повний текст джерелаGuillaume, Alexandre. "Transitions de phases dans les fermions lourds sous contrainte uniaxiale." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10060.
Повний текст джерелаde, Medeiros Varzielas Ivo. "Family symmetries and the origin of fermion masses and mixings." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497464.
Повний текст джерелаAllanach, Benjamin Christopher. "Supersymmetric extensions of the standard model and the fermion mass problem." Thesis, University of Southampton, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294624.
Повний текст джерелаWu, Jackson M. S. "Improvement of Wilson fermions and twisted mass lattice QCD /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/9706.
Повний текст джерелаDe, Asitkumar. "Spontaneous chiral symmetry breaking and fermion mass generation in Lattice field theories /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487591658176323.
Повний текст джерелаBrunton, Rosalind Elizabeth. "Strong correlation effects in heavy fermion and double exchange systems." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300345.
Повний текст джерелаGomes, Adriano Doff Sotta. "Alguns aspectos sobre a geração dinâmica de massa em modelos de Technicolor /." São Paulo : [s.n.], 2005. http://hdl.handle.net/11449/102510.
Повний текст джерелаBanca: Paulo Sérgio Rodrigues da Silva
Banca: Carlos Ourívio Escobar
Banca: Vicente Pleitez
Banca: Juan Carlos Montero Garcia
Resumo: O mecanismo de Higgs baseado na existência de um bóson escalar fundamental apresenta problemas de hierarquia e naturalidade. Neste trabalho revisitamos os aspectos mais gerais associados a modelos de Technicolor. Em particular, argumentamos que a auto-energia fermiônica deveria apresentar a forma conhecida como Irregular, a qual resolve a maioria dos problemas enfrentados por modelos que seguem esta linha. No último capítulo desta tese elaboramos um modelo, assumindo como solução a forma Irregular para a auto-energia fermiônica, onde as três gerações de férmions adquirem massa via efeitos de quebra dinâmica de simetria.
Abstracts: The Higgs mechanism, based on existence of fundamental scalars bosons suffer from the hierarchy and naturalness problems. In this work we review the main aspects of the Technicolor models. In particular, we aegue that the fermionic self-energy must behave as the Irregular form, that solve most of the Technicolor models problems. In the last Chapter of his thesis we build a model, assuming the Irregular form for the fermionic self-energy, where the three fermionic generations receive mass dynamically.
Doutor
Harrington, A. P. "Enhanced masses and superconductivity in highly correlated fermionic systems." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233549.
Повний текст джерелаDück, Alexander [Verfasser], and Werner [Akademischer Betreuer] Rodejohann. "Phenomenology of Neutrinos and Possible SO(10) Origins of Fermion Masses and Mixings / Alexander Dück ; Betreuer: Werner Rodejohann." Heidelberg : Universitätsbibliothek Heidelberg, 2012. http://d-nb.info/1177148234/34.
Повний текст джерелаDrach, Vincent. "Fermions twistés dynamiques et spectroscopie des baryons." Phd thesis, Université de Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00633497.
Повний текст джерелаHarraud, Pierre-Antoine. "Etude de la structure du nucléon par des calculs de QCD sur réseau avec des fermions de masse twistée." Phd thesis, Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00546526.
Повний текст джерелаMontefiori, Samuele. "Anomalies in the stress tensor of a chiral fermion in a gauge background." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18793/.
Повний текст джерелаTsang, Justus Tobias. "Continuum limit of D and Ds decay constants with Moebius domain wall fermions at physical pion masses." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/405419/.
Повний текст джерелаMollet, Simon. "Exploration of 6-dimensional models with non trivial topology and their predictions for fermions masses and mixings, neutrino physics, flavour changing interactions and CP violation." Doctoral thesis, Universite Libre de Bruxelles, 2016. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/230863.
Повний текст джерелаDoctorat en Sciences
info:eu-repo/semantics/nonPublished
Zeidlewicz, Lars [Verfasser], Owe [Akademischer Betreuer] Philipsen, and Gernot [Akademischer Betreuer] Münster. "The thermal transition of quantum chromodynamics with Twisted Mass Fermions / Lars Zeidlewicz. Gutachter: Owe Philipsen ; Gernot Münster." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2011. http://d-nb.info/1043947493/34.
Повний текст джерелаGomes, Adriano Doff Sotta [UNESP]. "Alguns aspectos sobre a geração dinâmica de massa em modelos de Technicolor." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/102510.
Повний текст джерелаFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O mecanismo de Higgs baseado na existência de um bóson escalar fundamental apresenta problemas de hierarquia e naturalidade. Neste trabalho revisitamos os aspectos mais gerais associados a modelos de Technicolor. Em particular, argumentamos que a auto-energia fermiônica deveria apresentar a forma conhecida como Irregular, a qual resolve a maioria dos problemas enfrentados por modelos que seguem esta linha. No último capítulo desta tese elaboramos um modelo, assumindo como solução a forma Irregular para a auto-energia fermiônica, onde as três gerações de férmions adquirem massa via efeitos de quebra dinâmica de simetria.
Abstracts: The Higgs mechanism, based on existence of fundamental scalars bosons suffer from the hierarchy and naturalness problems. In this work we review the main aspects of the Technicolor models. In particular, we aegue that the fermionic self-energy must behave as the Irregular form, that solve most of the Technicolor models problems. In the last Chapter of his thesis we build a model, assuming the Irregular form for the fermionic self-energy, where the three fermionic generations receive mass dynamically.
Capdevilla, Roldan Rodolfo Maia [UNESP]. "Dynamical chiral symmetry breaking: the fermionic gap equation with dynamical gluon mass and confinement." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/92026.
Повний текст джерелаAlguns aspectos da quebra de simetria quiral para quarks na representação fundamental são discutidos no contexto das equações de Schwinger-Dyson. Estudamos a equação de gap fermionica incluindo o efeito de uma massa dinêmica para os gluons. Ao estudar esta equação de gap verificamos que a intenção não é forte o suficiente para gerar uma massa dinâmica dos quarks compatível com os dados experimentais. Também discutimos como a introdução de um propagador confinante pode mudar este cenário, exatamente como foi proposto por Cornwall [1] recentemente, desta forma estudamos uma equação de gap completa, composta pela troca de um gluon massivo e por um termo confinante; M('p POT 2') = 'M IND. c('p POT 2') + 'M IND. 1g'('p POT 2'). Encontramos soluções assintótica desta equação de gap nos casos de constante de acoplamento constante e corredora. Este último caso corresponde a um aprimoramento do cálculo com constante de acoplamento constante feito por Doff, Machado e Natale [2]
Some aspects of chiral symmetry breaking for quarks in the fundamental representation are discussed in the framework of the Schwinger-Dyson equations. We study the fermionic gap equation including effects of dynamical gluon mass. Studying the bifurcation equation of this gap equation we verify that the interaction is not strong enough to generate a satisfactory dynamical quark mass. We also discuss how the introduction of a confining propagator may change this scenario as recently pointed out by Cornwall [1], so we study a complete gap equation composed by the one-dressed-gluon exchange term and a confining term: M('p POT 2') = 'M IND. c('p POT 2') + 'M IND. 1g'('p POT 2'). We find asymptotic solutions for this gap equation in the cases of constant coupling and running coupling constant. This last case is an improvement of the constant coupling calculation of Doff, Machado and Natale [2]
Capdevilla, Roldan Rodolfo Maia. "Dynamical chiral symmetry breaking : the fermionic gap equation with dynamical gluon mass and confinement /." São Paulo, 2013. http://hdl.handle.net/11449/92026.
Повний текст джерелаBanca: Adriano Doff Sotta Gomes
Banca: Alex Gomes Dias
Resumo: Alguns aspectos da quebra de simetria quiral para quarks na representação fundamental são discutidos no contexto das equações de Schwinger-Dyson. Estudamos a equação de gap fermionica incluindo o efeito de uma massa dinêmica para os gluons. Ao estudar esta equação de gap verificamos que a intenção não é forte o suficiente para gerar uma massa dinâmica dos quarks compatível com os dados experimentais. Também discutimos como a introdução de um propagador confinante pode mudar este cenário, exatamente como foi proposto por Cornwall [1] recentemente, desta forma estudamos uma equação de gap "completa", composta pela troca de um gluon massivo e por um termo confinante; M('p POT 2') = 'M IND. c('p POT 2') + 'M IND. 1g'('p POT 2'). Encontramos soluções assintótica desta equação de gap nos casos de constante de acoplamento "constante" e "corredora". Este último caso corresponde a um aprimoramento do cálculo com constante de acoplamento "constante" feito por Doff, Machado e Natale [2]
Abstract: Some aspects of chiral symmetry breaking for quarks in the fundamental representation are discussed in the framework of the Schwinger-Dyson equations. We study the fermionic gap equation including effects of dynamical gluon mass. Studying the bifurcation equation of this gap equation we verify that the interaction is not strong enough to generate a satisfactory dynamical quark mass. We also discuss how the introduction of a confining propagator may change this scenario as recently pointed out by Cornwall [1], so we study a "complete" gap equation composed by the one-dressed-gluon exchange term and a confining term: M('p POT 2') = 'M IND. c('p POT 2') + 'M IND. 1g'('p POT 2'). We find asymptotic solutions for this gap equation in the cases of "constant coupling" and "running coupling constant". This last case is an improvement of the constant coupling calculation of Doff, Machado and Natale [2]
Mestre
Hepburn, Derek John. "Light hadron spectrum, quark masses and meson decay constants from lattice QCD with O(a)-improved dynamical Wilson fermions." Thesis, University of Edinburgh, 2003. http://hdl.handle.net/1842/15009.
Повний текст джерелаPricopi, Lucia. "Etude de la masse effective des fermions lourds CeAl2 et CeRu2Si2 par mesures de l'effet de Haas-van Alphen sous champs magnétiques pulsés." Toulouse 3, 2001. http://www.theses.fr/2001TOU30044.
Повний текст джерелаPientka, Grit. "Hadronic corrections to electroweak observables from twisted mass lattice QCD." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17312.
Повний текст джерелаFor several benchmark quantities investigated to detect signs for new physics beyond the standard model of elementary particle physics, lattice QCD currently constitutes the only ab initio approach available at small momentum transfers for the computation of non-perturbative hadronic contributions. Among those observables are the lepton anomalous magnetic moments and the running of the electroweak coupling constants. We compute the leading QCD contribution to the muon anomalous magnetic moment by performing lattice QCD calculations on ensembles incorporating Nf=2+1+1 dynamical twisted mass fermions. Considering active up, down, strange, and charm quarks, admits for the first time a direct comparison of the lattice data for the muon anomaly with phenomenological results because both the latter as well as the experimentally obtained values are sensitive to the complete first two generations of quarks at the current level of precision. Recently, it has been noted that improved measurements of the electron and tau anomalous magnetic moments might also provide ways of detecting new physics contributions. Therefore, we also compute their leading QCD contributions, which simultaneously serve as cross-checks of the value obtained for the muon. Additionally, we utilise the obtained data to compute the leading hadronic contribution to the running of the fine structure constant, which enters all perturbative QED calculations. Furthermore, we show that even for the weak mixing angle the leading QCD contribution can be computed from this data. In this way, we identify a new prime observable in the search for new physics whose hadronic contributions can be obtained from lattice QCD. With the results obtained in this thesis, we are able to exclude unsuitable phenomenologically necessary flavour separations and thus directly assist the presently more precise phenomenological determinations of this eminent quantity.
Delplace, Pierre. "Etats de bord et cônes de Dirac dans des cristaux bidimensionnels." Paris 11, 2010. http://www.theses.fr/2010PA112354.
Повний текст джерелаThis thesis in physics constitutes a theoretical study of the edge states in bi-dimensional crystals which exhibit two Dirac cones (spin degenerated) in their dispersion relation. The two systems considered are graphene and the square lattice with half a magnetic quantum flux per plaquette. The analytical description of the dispersive energy levels in a high magnetic field (quantum Hall effect regime) due to the presence of edges is highlighted. According to the geometry of the crystal lattice and the shape of the edge, different kinds of coupling are induced between the components of the wave function. This gives rise to various structures of edge sates which however can be described in a common way. Without any magnetic field, some edge states can also exist in these systems, but they have a different origin and their existence itself depends on the shape of the edge. In the case of graphene, we show how to connect the existence of these edge states with a particular type of Berry phase, the so-called Zak phase. This approach allows, for instance, to understand how to manipulate these edge states by tuning the bulk parameters, what involves a topological transition of the Zak phase. Another type of topological transition has also been studied. It consists in the merging of the Dirac cones in the square lattice with half a quantum flux. We show that the mechanism leading to such a phenomena strongly differs from the one known in graphene, and that the physics around the transition can however be described within the same effective Hamiltonian. A shorter second part deals with the weak localization on a disordered cylinder with electronic interactions. The aim of this study is to illustrate the role of the geometry in the decoherence mechanisms due to electron-electron interactions in diffusive systems. The harmonics of the weak localization correction calculated reveal different regimes which probe the different length scales characterizing the decoherence. These lengths underline the sensibility of coherent processes to the geometry and are characterized by specified power laws in temperature
Rogério, Rodolfo José Bueno [UNESP]. "Aspectos clássicos e quânticos de espinores de dinânima não-usual: espinores de dimenssão de massa um." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/158276.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Na presente tese apresentaremos de forma detalhada o estudo sistemático de uma teoria quântica com férmions de dimensão de massa um que obedecem as estatísticas de Fermi-Dirac, abordando essencialmente sua construção, quantização do campo, análise dos observáveis físicos e aplicações quânticas. Forneceremos todos os detalhes de uma descoberta teórica inesperada da partícula de spin $1/2$ que compõe um conjunto completo de autoespinores com helicidade dual do operador conjugação de carga. Esses espinores recebem o nome de Elko, um acrônimo proveniente do Alemão \textit{Eigenspinoren des Ladungskonjugationsoperators}. Veremos que o elo entre os espaços de representação $(1/2, 0)$ e $(0, 1/2)$ não é dado pela simetria de paridade mas sim pela ``Mágica das matrizes de Pauli'', e, portanto, como consequência a dinâmica de tais campos será regida única e exclusivamente pela dinâmica de Klein-Gordon. Tal fato faz com que o propagador associado ao Elko guarde muita similaridade com o propagador do campo escalar. Intrinsicamente, em sua formulação embrionária, as somas de spin para o Elko mostram um termo que quebra explicitamente a covariância relativística, levando então à apreciação da \textit{Very Special Relativity}, que nada mais é do que um subgrupo do grupo de Lorentz, cuja álgebra deixa as somas de spin invariantes ou covariantes. Entretanto, mostraremos que existe uma liberdade na definição da estrutura dual, a qual permite que seja construída uma teoria local e invariante por transformações de Lorentz, levando, assim, a uma nova física bastante interessante e promissora.
The present thesis covers in details a systematic study of a quantum theory based on mass dimension one fermions which satisfy the Fermi-Dirac statistics, essentially addressing its construction, field quantization, analysis of physical observables and quantum applications. We provide all the details of an unexpected theoretical discovery of a spin 1/2 particle which composes a complete set of dual helicity spinors of the charge conjugation operator. Such spinors are called Elko, an acronym for the German word Eigenspinoren des Ladungskonjugationsoperators. We show that the relation between the representation spaces (1/2,0) and (0,1/2) is given by the “Magic of Pauli matrices” rather than parity symmetry, therefore, as a consequence the dynamic of such fields is governed solely and exclusively by the Klein-Gordon dynamic. Such fact makes the Elko propagator to be very similar to the scalar field propagator Intrinsically, in its embryonic formulation, Elko spin sums shows up a term that explicitly breaks relativistic covariance, leading to the appreciation of Very Special Relativity, a theory which is based on a subgroup of the Lorentz group, whose algebra leaves the spin sums invariant or covariant. However, we show a freedom in the dual structure definition, which allows the construction of a local and Lorentz invariant theory, thus, leading to a very interesting and promising new physics
Deppisch, Thomas Ludwig [Verfasser], and U. [Akademischer Betreuer] Nierste. "A Tale of Scales - Fermion Masses and Mixing in Minimal Supersymmetric SO($_10}$) and Resummation of Gluino Contributions to the MSSM Higgs Potential / Thomas Ludwig Deppisch ; Betreuer: U. Nierste." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1187343366/34.
Повний текст джерелаCavalcante, Everton. "Decaimento do próton e massa dos léptons numa extensão de gauge do modelo padrão." Universidade Federal da Paraíba, 2011. http://tede.biblioteca.ufpb.br:8080/handle/tede/5700.
Повний текст джерелаCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this dissertation we will approach the lepton and barion number simmetries as low energy manifestation of more fundamental theories at higher energies. By using effective operators we investigate the possibility of generating reasonable mass terms for leptons as well as suppressed proton lifetime in the Standard Model. We also look at the proton decay processes in a specific grand unified theory (the minimal SU(5)) and comment about the experimental bounds on proton lifetime from Superkamiokande. Finally, we consider a simple gauge extension of Standard Model, the minimal SUC(3) SUL(3) UN(1) model, pointing some drawbaces in this model concerning lepton masses and proton lifetime. We study how it is possible to diminish its scalar content and solve the lepton mass and proton decay issues.
Nesta dissertação abordaremos as simetrias de número bariônico e leptônico do modelo padrão como manifestações em baixas energias de teorias mais fundamentais. Por meio de operadores efetivos, estudaremos termos de massa para léptons e modos de decaimento para o próton. Também estudaremos a predição quanto ao tempo de decaimento do próton num modelo de grande unificação específico (modelo SU(5) mínimo), comparando com o limite experimental do Super-Kamiokande. Por último apontaremos alguns problemas numa extensão de gauge do modelo padrão (modelo SUC(3) SUL(3) UN(1) mínimo), diminuindo seu conteúdo de campos escalares, onde os operadores efetivos para massa dos léptons e decaimento do próton serão manipulados através da introdução de certas simetrias discretas.
Almutairi, Alanoud. "Electronic band structure equations and Fermi surface evolution from 2D materials to 3D layered superconducting compounds." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/134414/1/Alanoud%20Mulfi%20Z_Almutairi_Thesis.pdf.
Повний текст джерелаWeiland, Cedric. "Effects of fermionic singlet neutrinos on high- and low-energy observables." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00922999.
Повний текст джерелаButtazzo, Dario. "Implications of the discovery of a Higgs boson with a mass of 125 GeV." Doctoral thesis, Scuola Normale Superiore, 2013. http://hdl.handle.net/11384/85868.
Повний текст джерелаTaylor, Paul Andrew. "Nuclear Binding Energy in Terms of a Redefined (A)symmetry Energy." Thesis, Boston College, 2004. http://hdl.handle.net/2345/460.
Повний текст джерелаWe investigate the structure of the equation of state of finite nuclear matter by examining the nature of isospin dependence in the (a)symmetry energy term. In particular, we include in the description of the binding energy fourth-order dependence with respect to the asymmetry factor, (N-Z)/A, and the regime of the l=0 Landau parameter, F0´ , is required to be less than –1. This modified equation predicts a minimum binding energy where N≠Z, in addition to the standard symmetric minimum when N=Z. Results with the new asymmetry energy term are compared with experimental binding and symmetry energies from standard semi-empirical mass formulas. Importantly, this method reveals one possible mechanism for producing the phenomenon of neutron excess which is seen in physical nuclei
Thesis (BS) — Boston College, 2004
Submitted to: Boston College. College of Arts and Sciences
Discipline: Physics
Discipline: College Honors Program
Pagano, Emanuele Vincenzo. "Space-time correlations of intermediate mass fragments emitted in Heavy ion reactions at Fermi energy by intensity interferometry studied with CHIMERA and perspectives." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3984.
Повний текст джерелаRasmussen, Rasmus Westphal. "Implications of physics beyond the Standard Model in the quark and lepton sectors." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19174.
Повний текст джерелаThe Standard Model (SM) of particle physics is a well-tested and predictive theory, however non-zero neutrino masses, the existence of dark matter, and the baryon asymmetry suggest physics beyond the SM. Thus, in order to have a model consistent with observations, a more complete theory is needed. Experimentally, one can search for new physics, thereby differentiate different BSM scenarios. We consider BSM scenarios in the quark and lepton sectors, and study their phenomenological consequence on measurable observables. A specific example is neutrino mass modeling with the introduction of sterile neutrinos. We study the phenomenological consequence of introducing them at different mass scales in the context of symmetry-generated or structureless neutrino mass models. We find distinct hierarchies among the flavor-dependent active-sterile mixings in the symmetry-generated mass models, which acts as a model discriminator for future experiments. Similarly as using symmetries in the neutrino sector, one can also use symmetries in quark mass models. This thesis consider symmetries capable of quantizing the Cabibbo quark mixing angle to leading order. As a result, a variety of possible symmetries are obtained, which can be used to build specific quark mass models. Probing BSM physics indirectly via astrophysical neutrinos, acts as an alternative to direct detection, and using the neutrino flavor composition as observable, BSM physics leads to clear deviations from expectation. Additional information comes from other effects, and it helps in constraining the parameter space further. Beside discussing different BSM scenarios, we illustrate the potential of future experiments, emphasizing their effectiveness to test and discriminate BSM physics.
Resende, Bruno Messias Farias de. "Modelos matemáticos para isolantes topológicos em redes." Universidade Federal de Uberlândia, 2017. http://dx.doi.org/10.14393/ufu.di.2018.90.
Повний текст джерелаSistemas descritos por Hamiltonianos do tipo Dirac são ubíquos. Surgindo em materiais como grafeno, isolantes topológicos ou recentemente nos semimetais de Weyl. Devido ao interesse tecnológico e acadêmico desses materiais, caracterizar suas propriedades é essencial. Uma abordagem matemática para efetuar o estudo de tais sistemas consiste em discretizar o Hamiltoniano no espaço das posições, mas tal abordagem esbarra no problema da duplicação de férmions. De forma breve, esse problema atesta pela impossibilidade de simulação de férmions livres não massivos em uma rede discreta sem que alguma simetria ou propriedade da Hamiltoniana seja quebrada. No presente trabalho demonstramos que tal problemática não deveria ser causa de preocupação para o estudo de sistemas na matéria condensada, pois podemos utilizar a simetria quebrada para confinar os portadores de carga no sistema para remover os estados duplicados. Tal remoção é conseguida com a inserção de um termo quadrático em relação ao momento, conhecido como massa de Wilson. Nesse sentido podemos inserir um termo de Wilson com quebra de simetria necessária para o confinamento, tornando o problema de duplicação de férmions irrelevante, essa relação não tinha sido notada até o presente trabalho, e recentes resultados na literatura erroneamente atribuem a massa de Wilson com a quebra de uma simetria de reversão temporal, o que não necessariamente é verdade. Nesse contexto além de abordar essa relação a presente dissertação objetiva também elucidar alguns mal entendimentos a respeitos das massas de Wilson, quiralidade e outras simetrias. Para validar nosso argumento central estudamos diversos sistemas de interesse e comparamos com os resultados na literatura.
Hamiltonians of Dirac type are ubiquitous. Appearing in materials such as graphene, topological insulators or recently in the Weyl semimetals. Due to the technological and academic interest of these materials, characterizing their properties is essential. A mathematical approach to study these systems consists of discretizing the Hamiltonian in the space of positions, but such an approach causes the problem of doubling fermions (FDP). We demonstrate the FDP should not be a cause of concern for the study of confined systems because we can use the broken symmetry to confine in the system to remove the duplicate states. Such removal is achieved by inserting a quadratic term with respect to the moment, known as the Wilson mass. In this sense we can insert a Wilson term with symmetry breaking required for confinement, rendering the fermion duplication problem irrelevant, this relationship had not been noticed until the present work, and recent literature results erroneously attribute Wilson’s mass to break of a symmetry of time reversal, which is not necessarily true. In this context, in addition to addressing this relationship, the present dissertation also aims to elucidate some misconceptions regarding the Wilson masses, chirality and other symmetries. In order to validate our central argument we study several systems of interest and compare it with the results in the literature.
Dissertação (Mestrado)
Dann, Martin Richard. "Experimental study of two dimensional fluid and solid '3He adsorbed on preplated graphite." Thesis, Royal Holloway, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325525.
Повний текст джерелаNalpas, Laurent. "Propriétés et Modes de désexcitation des noyaux chauds observés dans la réaction 36Ar sur 58Ni avec le détecteur INDRA." Phd thesis, Université Paris Sud - Paris XI, 1996. http://tel.archives-ouvertes.fr/tel-00083951.
Повний текст джерелаSelon l'énergie d'excitation mise en jeu, plusieurs modes de décroissance sont observés, en particulier une émission de fragments complexes (Z>2), dont l'origine est encore mal comprise.
Le GANIL permet d'explorer sur une large gamme en énergie, entre 32 et 95 MeV/u, la fonction d'excitation du système Ar+Ni depuis l'« évaporation » jusqu'à la «vaporisation » complète des noyaux chauds en particules légères (neutrons, isotopes de H, He).
L'analyse des mécanismes de réaction a montré, pour des petits paramètres d'impact, la domination des collisions binaires très inélastiques.
Ces dernières ont motivé une analyse en deux sources, des événements bien mesurés par le détecteur INDRA, à l'aide d'une méthode de reconstruction fondée sur l'«arbre minimum».
Des énergies d'excitation voisines de 20 MeV/A sont atteintes, à 95 MeV/u, dans les collisions centrales.
Pour les collisions violentes, le partage de l'énergie n'est plus équilibrée entre les deux partenaires, le quasiprojectile ayant une énergie d'excitation par nucléon plus élevée que la quasi-cible.
Entre 2 et 8 MeV/A d'énergie d'excitation totale du système, correspond une phase de production importante de fragments de masses intermédiaires qui sature autour de 10 MeV/A.
Le déclin du régime de «multifragmentation», au-delà de 15 MeV/A, coïncide avec la probabilité croissante d'observer la «vaporisation» des deux noyaux chauds, dont le seuil se situe aux environs de 8 MeV/A.
Par ailleurs, l'augmentation régulière de la température extraite des rapports isotopiques He-Li en fonction de l'énergie d'excitation du quasi-projectile suggère une évolution progressive des modes de décroissance des noyaux chauds, en accord avec les prédictions de modèles statistiques.
Aucun signe d'une transition de phase du premier ordre de type liquide-gaz n'est observé pour ces noyaux légers.
Lam, Yek Wah. "Isospin symmetry breaking in sd shell nuclei." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14446/document.
Повний текст джерелаIn the thesis, we develop a microscopic approach to describe theisospin-symmetry breaking effects in sd-shell nuclei.The work is performed within the nuclear shell model.A realistic isospin-conserving Hamiltonian is supplementedby a charge-dependent part consisting of the Coulomb interaction andYukawa-type meson exchange potentials to model charge-dependent forces ofnuclear origin. The extended database of the experimental isobaric mass multiplet equation coefficients is compiled during the thesis work and is used in a fit of the Hamiltonian parameters.The constructed Hamiltonian provides an accurate theoretical description ofthe isospin mixing nuclear states. A specific behaviour of the IMME coefficients have been revealed.We present two important applications (i) calculations of isospin-forbiddenproton emission amplitudes, which is often of interest for nuclearastrophysics, and (ii) calculation on corrections to nuclear Fermi beta decay, which is crucial for the tests of fundamental symmetries of the weak interaction
Soddu, Andrea. "Models of fermion masses /." 2003. http://wwwlib.umi.com/dissertations/fullcit/3091138.
Повний текст джерела"A bottom-up approach to fermion masses." Université catholique de Louvain, 2008. http://edoc.bib.ucl.ac.be:81/ETD-db/collection/available/BelnUcetd-12032008-232938/.
Повний текст джерелаAyyar, Venkitesh. "Fermion Mass Generation without Spontaneous Symmetry Breaking." Diss., 2016. http://hdl.handle.net/10161/12855.
Повний текст джерелаThe conventional mechanism of fermion mass generation in the Standard Model involves Spontaneous Symmetry Breaking (SSB). In this thesis, we study an alternate mechanism for the generation of fermion masses that does not require SSB, in the context of lattice field theories. Being inherently strongly coupled, this mechanism requires a non-perturbative approach like the lattice approach.
In order to explore this mechanism, we study a simple lattice model with a four-fermion interaction that has massless fermions at weak couplings and massive fermions at strong couplings, but without any spontaneous symmetry breaking. Prior work on this type of mass generation mechanism in 4D, was done long ago using either mean-field theory or Monte-Carlo calculations on small lattices. In this thesis, we have developed a new computational approach that enables us to perform large scale quantum Monte-Carlo calculations to study the phase structure of this theory. In 4D, our results confirm prior results, but differ in some quantitative details of the phase diagram. In contrast, in 3D, we discover a new second order critical point using calculations on lattices up to size $ 60^3$. Such large scale calculations are unprecedented. The presence of the critical point implies the existence of an alternate mechanism of fermion mass generation without any SSB, that could be of interest in continuum quantum field theory.
Dissertation
陳依婷. "Neutrino Masses Through Zee Mechanism in 5D Split Fermion Model." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/73124117256746341790.
Повний текст джерела國立清華大學
物理學系
97
The phenomenon of neutrino oscillation implies that neutrinos have masses, and the flavor eigenbasis is not the mass eigenbasis, so neutrinos oscillate between different flavor states while traveling. Thus it is beyond the Standard Model, and it calls for new physics.Here we study the Zee model and Extra dimensions to explain the neutrino oscillation. First, suppose there exists a compactied fth dimension, and neutrinos have Ma jorana masses through the 5 dimensional Zee model. Second, assume the fermions are localized on a 4 dimensional brane embedded in the 5 dimensional space-time by the Split Fermion model, while the higgs are free to propagate along the extra dimension. We can get the forms of parameters in the neutrino mass matrix from Zee model. Then, transforming with the PMNS matrix, we found ranges of charged lepton masses, neutrino masses and mixing angles, and so on. Based on Anthropic Principle, we compare them to the experiment data, and we get 4 possible solutions. We also check the branch ratios of 5 lepton flavor violating processes, and they also satisfy the experiment constraints. Thus this is a possible model.
Özer, Alp Deniz [Verfasser]. "SO(10) - grand unification and fermion masses / vorgelegt von Alp Deniz Özer." 2005. http://d-nb.info/978062906/34.
Повний текст джерелаGuo, Duo. "Fermion Low Modes in Lattice QCD: Topology, the η' Mass and Algorithm Development". Thesis, 2021. https://doi.org/10.7916/d8-knph-2598.
Повний текст джерелаBhatti, Abdul Aziz [Verfasser]. "Fermion masses and Higgs physics in grand unified theories / submitted by Abdul Aziz Bhatti." 2010. http://d-nb.info/1002224055/34.
Повний текст джерелаKaczmarczyk, Jan. "Unconventional superconductivity in correlated fermion systems." Praca doktorska, 2011. https://ruj.uj.edu.pl/xmlui/handle/item/274855.
Повний текст джерелаWe study unconventional superconductivity in strongly correlated electron systems and in applied magnetic (Zeeman) field. The strong correlations among quasiparticles are accounted for by means of the Gutzwiller approximation within the statistically-consistent scheme proposed recently in our group. We analyze the situation for a gas of heavy quasiparticles and obtain a phase diagram on the magnetic field-temperature plane (for both two- and three-dimensional cases, including the s-wave- and d-wave-gap symmetry solutions). In low magnetic fields the system is in the Bardeen-Cooper-Schrieffer (BCS) phase, whereas for the increasing magnetic field a transition to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase with nonzero Cooper pair momentum takes place. To distinguish novel features of the case with strong correlations we compare our results with those for a noncorrelated situation. In all analyzed situations the FFLO phase is more robust for the case with strong correlations, which implies that strong correlations stabilize the FFLO phase (and possibly other high-field low-temperature unconventional phases). We explain the stabilization mechanism. Next, we study conductance of a normal metal - strongly-correlated superconductor junction in order to provide an experimental test of our results. The conductance spectra in the cases with and without strong correlations differ essentially, and the differences should be easily observable experimentally, providing a hallmark of strong correlations in the superconducting state. Namely, correlations alter the distance between the conductance peaks for carriers with spin-up and spin-down. In the non-correlated case this distance is twice the Zeeman energy. In the correlated case this distance is about 30-50% smaller, but in other models it may be larger, depending on details of the electronic structure. Additionally, we perform analysis of the coexistence of antiferromagnetism (AF) and superconductivity (SC) within t-J model for a system with strong correlations and in applied magnetic field in the Pauli limit. The coexisting phase exhibits two superconducting gaps (a consequence of the AF and SC coexistence): singlet and staggered-triplet. The triplet component has a nonzero Cooper pair momentum, and can be viewed as an analogue of the FFLO phase. We obtain a phase diagram on the band filling - magnetic field plane. For band filling close to unity (i.e., close to the half-filled band situation) our results resemble those obtained recently in the heavy fermion system $CeCo(In_{1-x}Cd_{x})_{5}$. Namely, with the increasing magnetic field the system evolves from the coexisting phase, through AF phase, towards the spin-polarized normal state. Moreover, the onset of superconducting order decreases antiferromagnetic magnetization.
Urbach, Carsten [Verfasser]. "Wilson twisted mass fermions: towards realistic simulations of lattice QCD / Carsten Urbach." 2006. http://d-nb.info/978606612/34.
Повний текст джерела