The 125 GeV boson: A composite scalar?

Assuming that the 125 GeV particle observed at the LHC is a composite scalar and responsible for the electroweak gauge symmetry breaking, we consider the possibility that the bound state is generated by a non-Abelian gauge theory with dynamically generated gauge boson masses and a specific chiral symmetry breaking dynamics motivated by confinement. The scalar mass is computed with the use of the Bethe-Salpeter equation and its normalization condition as a function of the SU(N) group and the respective fermionic representation. If the fermions that form the composite state are in the fundamental representation of the SU(N) group, we can generate such light boson only for one specific number of fermions for each group. In the case of small groups, like SU(2) to SU(5), and two fermions in the adjoint representation we find that is quite improbable to generate such light composite scalar.Comment: 24 pages, 5 figures, discussion extended, references added; version to appear in Phys. Rev.

Quantização da carga ele'trica em teorias com grupo de Gauge semisimples

Orientador: Felice PisanoDissertação(mestrado)- Universidade Federal do Paraná. Setor de Ciências Exatas. Curso de Pós-Graduação em FísicaInclui bibliografi

Revision of previous Fontan connections to total extracardiac cavopulmonary anastomosis: A multicenter experience

AbstractBackground: Conversion to total extracardiac cavopulmonary anastomosis is an option for managing patients with dysfunction of a prior Fontan connection. Methods: Thirty-one patients (19.9 ± 8.8 years) underwent revision of a previous Fontan connection to total extracardiac cavopulmonary anastomosis at four institutions. Complications of the previous Fontan connection included atrial tachyarrhythmias (n = 20), progressive heart failure (n = 17), Fontan pathway obstruction (n = 10), effusions (n = 10), pulmonary venous obstruction by an enlarged right atrium (n = 6), protein-losing enteropathy (n = 3), right atrial thrombus (n = 2), subaortic stenosis (n = 1), atrioventricular valve regurgitation (n = 3), and Fontan baffle leak (n = 5). Conversion to an extracardiac cavopulmonary connection was performed with a nonvalved conduit from the inferior vena cava to the right pulmonary artery, with additional procedures as necessary. Results: There have been 3 deaths. Two patients died in the perioperative period of heart failure and massive effusions. The third patient died suddenly 8 months after the operation. All surviving patients were in New York Heart Association class I (n = 20) or II (n = 7), except for 1 patient who underwent heart transplantation. Early postoperative arrhythmias occurred in 10 patients: 4 required pacemakers, and medical therapy was sufficient in 6. In 15 patients, pre-revision arrhythmias were improved. Effusions resolved in all but 1 of the patients in whom they were present before revision. The condition of 2 patients with protein-losing enteropathy improved within 30 days. Conclusions: Conversion of a failing Fontan connection to extracardiac cavopulmonary connection can be achieved with low morbidity and mortality. Optimally, revision should be undertaken early in symptomatic patients before irreversible ventricular failure ensues. (J Thorac Cardiovasc Surg 2000;119:340-6

Quantização da carga ele'trica em teorias com grupo de Gauge semisimples

Orientador: Felice PisanoDissertação(mestrado)- Universidade Federal do Paraná. Setor de Ciências Exatas. Curso de Pós-Graduação em FísicaInclui bibliografi

Uma simples análise do equilíbrio do monociclista

Neste trabalho, discutimos o movimento de um monociclo. Em particular analisamos as condições para manter o equilíbrio do monociclista. Considerando um modelo baseado em um pêndulo invertido, determinamos as freqüências que proporcionam ao monociclista uma posição de equilíbrio. Esta situação corresponde ao mínimo da energia potencial

Caracterização do momento magnético de ímãs de neodímio e uma abordagem didática para anomalia (g-2) do múon

Neste trabalho, considerando um modelo simplificado, estimamos o momento magnético m ¯, associado a dois ímãs de neodímio com diferentes geometrias. Investigamos como o efeito da temperatura modifica propriedades magnéticas, como a intensidade do campo magnético avaliada no extremo destes magnetos, a partir destes resultados apresentamos uma anomalia fictícia de cunho didático inspirado na discussão construída ao longo do trabalho, que permite ilustrar um problema atual no cenário de física de altas energias, conhecido como anomalia (g-2) do múon

The 125 GeV boson : a composite scalar?

Assuming that the 125 GeV particle observed at the LHC is a composite scalar and responsible for the electroweak gauge symmetry breaking, we consider the possibility that the bound state is generated by a non-Abelian gauge theory with dynamically generated gauge boson masses and a specific chiral symmetry breaking dynamics motivated by confinement. The scalar mass is computed with the use of the Bethe- Salpeter equation and its normalization condition as a function of the SUðNÞ group and the respective fermionic representation. If the fermions that form the composite state are in the fundamental representation of the SUðNÞ group, we can generate such a light boson only for one specific number of fermions for each group. We address the uncertainties underlying this result, when considering the strong dynamics in isolation

DYNAMICAL SYMMETRY BREAKING IN A MINIMAL 3-3-1 MODEL

The gauge symmetry breaking in some versions of 3-3-1 models can be implemented dynamically because at the scale of a few TeVs the U(1)(X) coupling constant becomes strong. In this work, we consider the dynamical symmetry breaking in a minimal SU(3)(TC) x SU(3)(L) x U(1)(X) model, where we propose a new scheme to cancel the chiral anomalies, including two-index symmetric (6) technifermions, which incorporates naturally the walking behavior in the Technicolor (TC) sector. The composite scalar content of the model is minimal and all the symmetry breaking is implemented by a multiplet of technifermions. The choice of TC representations not only provides the anomaly cancelation with a walking behavior, but is crucial to promote the model's full dynamical symmetry breaking. We consider the dynamical generation of technigluon masses and, depending on the 3-3-1 symmetry breaking scale (mu(331)), we verify that the technigluon mass is strongly linked to the Z' mass scale, for instance, if mu(331) = 1 TeV, we have M-Z' > 1 TeV only if M-TG < 350 GeV.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq