Neutrino masses and mixing in A(4) models with three Higgs doublets

We study neutrino masses and mixing in the context of flavor models with A(4) symmetry, three scalar doublets in the triplet representation, and three lepton families. We show that there is no representation assignment that yields a dimension-5 mass operator consistent with experiment. We then consider a type-I seesaw with three heavy right-handed neutrinos, explaining in detail why it fails, and allowing us to show that agreement with the present neutrino oscillation data can be recovered with the inclusion of dimension-3 heavy neutrino mass terms that break softly the A(4) symmetry.

Stability of the tree-level vacuum in two Higgs doublet models against charge or CP spontaneous violation

We show that in two Higgs doublet models at tree-level the potential minimum preserving electric charge and CP symmetries, when it exists, is the global one. Furthermore, we derived a very simple condition, involving only the coefficients of the quartic terms of the potential, that guarantees spontaneous CP breaking. (C) 2004 Elsevier B.V. All rights reserved.

Abelian realization of phenomenological two-zero neutrino textures

In an attempt at explaining the observed neutrino mass-squared differences and leptonic mixing, lepton mass matrices with zero textures have been widely studied. In the weak basis where the charged lepton mass matrix is diagonal, various neutrino mass matrices with two zeros have been shown to be consistent with the current experimental data. Using the canonical and Smith normal form methods, we construct the minimal Abelian symmetry realizations of these phenomenological two-zero neutrino textures. The implementation of these symmetries in the context of the seesaw mechanism for Majorana neutrino masses is also discussed. (C) 2014 The Authors. Published by Elsevier B.V.

Constraining multi-Higgs flavour models

To study a flavour model with a non-minimal Higgs sector one must first define the symmetries of the fields; then identify what types of vacua exist and how they may break the symmetries; and finally determine whether the remnant symmetries are compatible with the experimental data. Here we address all these issues in the context of flavour models with any number of Higgs doublets. We stress the importance of analysing the Higgs vacuum expectation values that are pseudo-invariant under the generators of all subgroups. It is shown that the only way of obtaining a physical CKM mixing matrix and, simultaneously, non-degenerate and non-zero quark masses is requiring the vacuum expectation values of the Higgs fields to break completely the full flavour group, except possibly for some symmetry belonging to baryon number. The application of this technique to some illustrative examples, such as the flavour groups Delta (27), A(4) and S-3, is also presented.

Theory and phenomenology of two-higgs-doublet models

We discuss theoretical and phenomenological aspects of two-Higgs-doublet extensions of the Standard Model. In general, these extensions have scalar mediated flavour changing neutral currents which are strongly constrained by experiment. Various strategies are discussed to control these flavour changing scalar currents and their phenomenological consequences are analysed. In particular, scenarios with natural flavour conservation are investigated, including the so-called type I and type II models as well as lepton-specific and inert models. Type III models are then discussed, where scalar flavour changing neutral currents are present at tree level, but are suppressed by either a specific ansatz for the Yukawa couplings or by the introduction of family symmetries leading to a natural suppression mechanism. We also consider the phenomenology of charged scalars in these models. Next we turn to the role of symmetries in the scalar sector. We discuss the six symmetry-constrained scalar potentials and their extension into the fermion sector. The vacuum structure of the scalar potential is analysed, including a study of the vacuum stability conditions on the potential and the renormalization-group improvement of these conditions is also presented. The stability of the tree level minimum of the scalar potential in connection with electric charge conservation and its behaviour under CP is analysed. The question of CP violation is addressed in detail, including the cases of explicit CP violation and spontaneous CP violation. We present a detailed study of weak basis invariants which are odd under CP. These invariants allow for the possibility of studying the CP properties of any two-Higgs-doublet model in an arbitrary Higgs basis. A careful study of spontaneous CP violation is presented, including an analysis of the conditions which have to be satisfied in order for a vacuum to violate CP. We present minimal models of CP violation where the vacuum phase is sufficient to generate a complex CKM matrix, which is at present a requirement for any realistic model of spontaneous CP violation.

A modelação nas tecnologias de tratamento de água – o caso particular do arrastamento por ar

Os recursos hídricos subterrâneos constituem a maior fonte disponível de água doce e são, cada vez mais, utilizados no abastecimento de água para consumo humano e em múltiplas actividades industriais e agrícolas. A poluição destes recursos, fruto de acidente ou negligência, é uma realidade que se verifica com uma frequência alarmante e que atinge níveis preocupantes no nosso país. Nestas Jornadas pretende-se apresentar, numa primeira fase, uma breve alusão à operação de arrastamento por ar em colunas com enchimento desordenado, e suas vantagens face a outros processos de despoluição e, numa segunda fase, a utilidade de desenvolvimento de modelos de simulação e optimização numérica desta operação unitária. Para tal, é exposta a formulação do modelo matemático fenomenológico concebido por Castro e Fiúza (Castro, 1997) desenvolvido sob uma fundamentação teórica com carácter sistémico, em termos de equações de balanço de massa para uma determinada secção de volume infinitesimal, traduzido num sistema de EDOs e num sistema de EDPs, para situações de estado estacionário e transiente respectivamente e são apresentados os resultados entretanto obtidos.

Cálculo 2 - Conceitos, Exercícios e Aplicações

Este livro pretende fornecer aos estudantes dos cursos de Engenharia um texto que seja, simultaneamente, elementar e rigoroso e que lhes permita aprender os conceitos básicos do cálculo infinitesimal e as suas aplicações. Conscientes da vastidão de possíveis caminhos a seguir na apresentação das matérias, os autores optaram por seguir uma sequência simples que tivesse em linha de conta os atuais ajustes dos objetivos da unidade curricular em que esta temática se enquadra, face à atual tendência para a diminuição dos tempos letivos e incentivo à utilização de software MATLAB. Neste sentido, este livro está organizado em três capítulos, ao longo dos quais se procurou obedecer a uma estrutura evolutiva em torno do rigor e da formalidade, mas sem excessos de nomenclatura. No primeiro capítulo estudam-se as funções reais de variável real, o segundo capítulo incide sobre o estudo da natureza de séries numéricas e funcionais e o terceiro capítulo destina-se ao cálculo integral. Em cada capítulo é proporcionado um conjunto de exercícios variados e não repetitivos, em número suficiente e equilibrado, apresentando-se alguns deles já resolvidos, propondo-se outros para resolução e ilustrando algumas aplicações práticas de integração de conhecimentos, recorrendo a software de cálculo algébrico e numérico.

Cálculo 1 - Conceitos, Exercícios e Aplicações

Este livro pretende fornecer aos estudantes dos cursos de Engenharia um texto que seja, simultaneamente, elementar e rigoroso e que lhes permita aprender os conceitos básicos do cálculo infinitesimal e as suas aplicações. Conscientes da vastidão de possíveis caminhos a seguir na apresentação das matérias, os autores optaram por seguir uma sequência simples que tivesse em linha de conta os atuais ajustes dos objetivos da unidade curricular em que esta temática se enquadra, face à atual tendência para a diminuição dos tempos letivos e incentivo à utilização de software MATLAB®. Neste sentido, este livro está organizado em três capítulos, ao longo dos quais se procurou obedecer a uma estrutura evolutiva em torno do rigor e da formalidade, mas sem excessos de nomenclatura. No primeiro capítulo estudam-se as funções reais de variável real, o segundo capítulo incide sobre o estudo da natureza de séries numéricas e funcionais e o terceiro capítulo destina-se ao cálculo integral. Em cada capítulo é proporcionado um conjunto de exercícios variados e não repetitivos, em número suficiente e equilibrado, apresentandose alguns deles já resolvidos, propondo-se outros para resolução e ilustrando algumas aplicações práticas de integração de conhecimentos, recorrendo a software de cálculo algébrico e numérico.

Angular distributions in t(t)over-barH(H -> b(b)over-bar) reconstructed events at the LHC

The associated production of a Higgs boson and a top-quark pair, t (t) over barH, in proton-proton collisions is addressed in this paper for a center of mass energy of 13 TeV at the LHC. Dileptonic final states of t (t) over barH events with two oppositely charged leptons and four jets from the decays t -> bW(+) -> bl(+)v(l), (t) over bar -> (b) over barW(-) -> (b) over barl(-)(v) over bar (l) and h -> b (b) over bar are used. Signal events, generated with MadGraph5_aMC@NLO, are fully reconstructed by applying a kinematic fit. New angular distributions of the decay products as well as angular asymmetries are explored in order to improve discrimination of t (t) over barH signal events over the dominant irreducible background contribution, t (t) over barb (b) over bar. Even after the full kinematic fit reconstruction of the events, the proposed angular distributions and asymmetries are still quite different in the t (t) over barH signal and the dominant background (t (t) over barb (b) over bar).

Constraint-based modeling of minimum set covering: application to species differentation

Work presented in the context of the European Master in Computational Logics, as partial requisit for the graduation as Master in Computational Logics

Study of forbidden transitions in atomic systems

A Thesis submitted for the co-tutelle degree of Doctor in Physics at Universidade Nova de Lisboa and Université Pierre et Marie Curie

Symmetry and order parameter dynamics of the human odometer

Bipedal gaits have been classified on the basis of the group symmetry of the minimal network of identical differential equations (alias cells) required to model them. Primary bipedal gaits (e.g., walk, run) are characterized by dihedral symmetry, whereas secondary bipedal gaits (e.g., gallop-walk, gallop- run) are characterized by a lower, cyclic symmetry. This fact has been used in tests of human odometry (e.g., Turvey et al. in P Roy Soc Lond B Biol 276:4309–4314, 2009, J Exp Psychol Hum Percept Perform 38:1014–1025, 2012). Results suggest that when distance is measured and reported by gaits from the same symmetry class, primary and secondary gaits are comparable. Switching symmetry classes at report compresses (primary to secondary) or inflates (secondary to primary) measured distance, with the compression and inflation equal in magnitude. The present research (a) extends these findings from overground locomotion to treadmill locomotion and (b) assesses a dynamics of sequentially coupled measure and report phases, with relative velocity as an order parameter, or equilibrium state, and difference in symmetry class as an imperfection parameter, or detuning, of those dynamics. The results suggest that the symmetries and dynamics of distance measurement by the human odometer are the same whether the odometer is in motion relative to a stationary ground or stationary relative to a moving ground.

Reduction, Linearization and stability of relative equilibria for mechanical systems on riemannian manifolds

Consider a Riemannian manifold equipped with an infinitesimal isometry. For this setup, a unified treatment is provided, solely in the language of Riemannian geometry, of techniques in reduction, linearization, and stability of relative equilibria. In particular, for mechanical control systems, an explicit characterization is given for the manner in which reduction by an infinitesimal isometry, and linearization along a controlled trajectory "commute." As part of the development, relationships are derived between the Jacobi equation of geodesic variation and concepts from reduction theory, such as the curvature of the mechanical connection and the effective potential. As an application of our techniques, fiber and base stability of relative equilibria are studied. The paper also serves as a tutorial of Riemannian geometric methods applicable in the intersection of mechanics and control theory.

Symmetric planar central configurations of five bodies: Euler plus two

We study planar central configurations of the five-body problem where three of the bodies are collinear, forming an Euler central configuration of the three-body problem, and the two other bodies together with the collinear configuration are in the same plane. The problem considered here assumes certain symmetries. From the three bodies in the collinear configuration, the two bodies at the extremities have equal masses and the third one is at the middle point between the two. The fourth and fifth bodies are placed in a symmetric way: either with respect to the line containing the three bodies, or with respect to the middle body in the collinear configuration, or with respect to the perpendicular bisector of the segment containing the three bodies. The possible stacked five-body central configurations satisfying these types of symmetries are: a rhombus with four masses at the vertices and a fifth mass in the center, and a trapezoid with four masses at the vertices and a fifth mass at the midpoint of one of the parallel sides.

Optimal robust estimates using the Hellinger distance

Optimal robust M-estimates of a multidimensional parameter are described using Hampel's infinitesimal approach. The optimal estimates are derived by minimizing a measure of efficiency under the model, subject to a bounded measure of infinitesimal robustness. To this purpose we define measures of efficiency and infinitesimal sensitivity based on the Hellinger distance.We show that these two measures coincide with similar ones defined by Yohai using the Kullback-Leibler divergence, and therefore the corresponding optimal estimates coincide too.We also give an example where we fit a negative binomial distribution to a real dataset of "days of stay in hospital" using the optimal robust estimates.