Search results for "Formulation"
showing 10 items of 265 documents
Two-Higgs leptonic minimal flavour violation
2011
We construct extensions of the Standard Model with two Higgs doublets, where there are flavour changing neutral currents both in the quark and leptonic sectors, with their strength fixed by the fermion mixing matrices $V_{CKM}$ and $V_{PMNS}$. These models are an extension to the leptonic sector of the class of models previously considered by Branco, Grimus and Lavoura, for the quark sector. We consider both the cases of Dirac and Majorana neutrinos and identify the minimal discrete symmetry required in order to implement the models in a natural way.
Triangular mass matrices of quarks and Cabibbo-Kobayashi-Maskawa mixing
1998
Every nonsingular fermion mass matrix, by an appropriate unitary transformation of right-chiral fields, is equivalent to a triangular matrix. Using the freedom in choosing bases of right-chiral fields in the minimal standard model, reduction to triangular form reduces the well-known ambiguities in reconstructing a mass matrix to trivial phase redefinitions. Furthermore, diagonalization of the quark mass sectors can be shifted to one charge sector only, without loosing the concise and economic triangular form. The corresponding effective triangular mass matrix is reconstructed, up to trivial phases, from the moduli of the CKM matrix elements, and vice versa, in a unique way. A new formula fo…
LHC-scale left-right symmetry and unification
2013
We construct a comprehensive list of nonsupersymmetric standard model extensions with a low-scale left-right (LR)-symmetric intermediate stage that may be obtained as simple low-energy effective theories within a class of renormalizable SO(10) grand unified theories. Unlike the traditional minimal LR models many of our example settings support a perfect gauge coupling unification even if the LR scale is in the LHC domain at a price of only (a few copies of) one or two types of extra fields pulled down to the TeV-scale ballpark. We discuss the main aspects of a potentially realistic model building conforming the basic constraints from the quark and lepton sector flavor structure, proton deca…
Nucleon and delta masses in QCD
1992
Using the positivity of the path integral measure of $QCD$ and defining a structure for the quark propagator in a background field according to the fluxon scenario for confinement, we calculate and compare the correlators for nucleon and delta. From their shape we elucidate about the origin of their mass difference, which in our simplified scenario is due to the tensor structure in the propagator. This term arises due to a dynamical mechanism which is responsible simultaneously for confinement and spontaneous chiral symmetry breaking. Finally we discuss, by comparing the calculated correlators with the Lehmann representation, the possibility that a strong CP and/or P violation occurs as a c…
Can (noncommutative) geometry accommodate leptoquarks?
1997
We investigate the geometric interpretation of the Standard Model based on noncommutative geometry. Neglecting the $S_0$-reality symmetry one may introduce leptoquarks into the model. We give a detailed discussion of the consequences (both for the Connes-Lott and the spectral action) and compare the results with physical bounds. Our result is that in either case one contradicts the experimental results.
Renormalized solutions for degenerate elliptic–parabolic problems with nonlinear dynamical boundary conditions and L1-data
2008
Abstract We consider a degenerate elliptic–parabolic problem with nonlinear dynamical boundary conditions. Assuming L 1 -data, we prove existence and uniqueness in the framework of renormalized solutions. Particular instances of this problem appear in various phenomena with changes of phase like multiphase Stefan problems and in the weak formulation of the mathematical model of the so-called Hele–Shaw problem. Also, the problem with non-homogeneous Neumann boundary condition is included.
Strategic Analysis Tools Application at SMEs in Ecuador
2015
This article explores the nature and scope of Strategic Analysis Tools (SAT) application in SMEs located in emerging countries such as Ecuador (where there are no formal studies on the subject). It is intended to assess which of the instruments utilized by these firms may contribute to formulate strategic options and which of them create awareness of relevant risks or distress specifically about continuity concerning their operations. Through the application of a survey to an intentional sample-selection of SMEs in Quito-Ecuador we analyzed the consciousness over these instruments to facilitate the creation of strategic options, their contribution to assess their competitive position and th…
Simple Strategic Analysis Tools at SMEs in Ecuador
2015
This article explores the possible applications of Strategic Analysis Tools (SAT) in SMEs located in emerging countries such as Ecuador (where there are no formal studies on the subject). It is intended to analyze if whether or not it is feasible to effectively apply a set of proposed tools to guide mental map decisions of executives when decisions on strategy have to be made. Through an in-depth review of the state of the art in regards to SAT and interviews performed to main participants such as chambers and executives of different firms, it is shown the feasibility of their application. This analysis is complemented with specialists´ interviews to deepen our insights and obtaining valid …
Development of digital health messages for rural populations in Tanzania: Multi- And interdisciplinary approach
2021
Background Health workers have traditionally delivered health promotion and education to rural communities in the Global South in paper leaflet formats or orally. With the rise of digital technologies, health promotion and education can be provided in innovative and more effective formats, which are believed to have a higher impact on disease prevention and treatment. Objective The aim of this tutorial is to illustrate how a multi- and interdisciplinary approach can be applied in the design process of digital health messages for use in the Global South. Methods The multi- and interdisciplinary team of the Non-discriminating access for Digital Inclusion (DigI) project digitalized and custom…
The Effects of Database Complexity on SQL Query Formulation (journal-first)
2020
The learning of practical Structured Query Language (SQL) skills often takes place in digital environments, where the learner writes queries against an exercise database. The exercise database is usually designed and implemented by the teacher, and populated with makeshift data. Although this approach is common, and SQL taught in almost all database courses, little scientific attention has been given to the nature of the exercise database.