scholarly journals FERMION MASSES AND MIXINGS IN GAUGE THEORIES

2002 ◽  
Vol 17 (28) ◽  
pp. 3981-4006 ◽  
Author(s):  
D. FALCONE

The recent evidence for neutrino oscillations stimulate us to discuss again the problem of fermion masses and mixings in gauge theories. In the standard model, several forms for quark mass matrices are equivalent. They become ansatze within most extensions of the standard model, where also relations between quark and lepton sectors may hold. In a seesaw framework, these relations can constrain the scale of heavy neutrino mass, which is often related to the scale of intermediate or unification gauge symmetry. As a consequence, two main scenarios arise. Hierarchies of masses and mixings may be explained by broken horizontal symmetries.

2008 ◽  
Vol 23 (14) ◽  
pp. 1011-1030 ◽  
Author(s):  
ION I. COTĂESCU ◽  
ADRIAN PALCU

The Pisano–Pleitez–Frampton 3-3-1 model is revisited here within the framework of the general method for solving gauge models with high symmetries. This exact algebraical approach — proposed several years ago by one of us — was designed to include a minimal Higgs mechanism that spontaneously breaks the gauge symmetry up to the universal U(1)em electromagnetic one and, consequently, to supply the mass spectrum and the couplings of the currents for all the particles in the model. We prove in this paper that this powerful tool, when is applied to the PPF 3-3-1 model, naturally recovers the whole Standard Model phenomenology and, in addition, predicts — since a proper parametrization is employed — viable results such as: (i) the exact expressions for the boson and fermion masses, (ii) the couplings of the charged and neutral currents and (iii) a plausible neutrino mass pattern. A generalized Weinberg transformation is implemented, while the mixing between the neutral bosons Z and Z′ is performed as a necessary step by the method itself. Some phenomenological consequences are also sketched, including the strange possibility that simultaneously m(Z) = m(Z′) and m(W) = m(V) hold.


1999 ◽  
Vol 14 (29) ◽  
pp. 1989-2001 ◽  
Author(s):  
D. FALCONE

A nearly historical account of quark mass matrix models is given, and the structure of quark mass matrices in the standard model is studied. For a minimal parameter basis suggested earlier, where Mu is diagonal and Md11, Md13, Md31 are zero, the dependence of mass matrices on the CP violating phase δ of V CKM is reported: all parameters are almost independent, except Md22 and Md23, and the equality |Md22| = Md23 is obtained for a value of δ very close to the value which is favored by experiments. Moreover, on this basis, Md12≃Md21 and Md33≃2Md32. Some comments on mass matrices in left–right symmetric models are added.


2000 ◽  
Vol 14 (19n20) ◽  
pp. 2051-2061
Author(s):  
AMITAVA RAYCHAUDHURI

Evidence in support of a nonzero neutrino mass, through the phenomenon of oscillations, is steadily becoming more compelling. A pedagogic introduction to vacuum neutrino oscillations and resonant flavour conversion is presented in this paper, prefaced by a thumbnail sketch of the relevant properties of the neutrino as embodied in the Standard Model of particle physics. The recent results from solar and atmospheric neutrinos are summarised and their combined implications on neutrino properties are outlined. Some attempts to incorporate a nonzero neutrino mass in extensions of the Standard Model are briefly discussed.


2020 ◽  
Vol 35 (09) ◽  
pp. 2050053
Author(s):  
Goran Senjanović ◽  
Vladimir Tello

In the LHC era the issue of the origin and nature of neutrino mass has attained a new meaning and a renewed importance. The growing success of the Higgs–Weinberg mechanism behind the charged fermion masses paves the way for answering the question of neutrino mass. We have shown recently how the spontaneous breaking of parity in the context of the minimal left–right symmetric model allows to probe the origin of neutrino mass in complete analogy with the charged fermions masses in the Standard Model. We revisit here this issue and fill in the gaps left in our previous work. In particular we discuss a number of different mathematical approaches to the problem of disentangling the seesaw mechanism and show how a unique analytical solution emerges. Most important, we give all the possible expressions for the neutrino Dirac mass matrix for general values of light and heavy neutrino mass matrices. In practical terms what is achieved is an untangling of the seesaw mechanism with clear and precise predictions testable at hadron colliders such as LHC.


2004 ◽  
Vol 19 (28) ◽  
pp. 4825-4833 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
TATSURU KIKUCHI ◽  
NOBUCHIKA OKADA

We examine supersymmetric contributions to transition magnetic moments of Majorana neutrinos. We first give the general formula for it. In concrete evaluations, informations of neutrino mass matrix elements including CP phases are necessary. Using unambiguously determined neutrino mass matrices in recently proposed minimal supersymmetric SO (10) model, the transition magnetic moments are calculated. The resultant neutrino magnetic moments with the input soft supersymmetry breaking masses being of order 1 TeV are found to be roughly an order of magnitude larger than those calculated in the standard model extended to incorporate the see-saw mechanism.


1991 ◽  
Vol 06 (12) ◽  
pp. 1089-1094 ◽  
Author(s):  
ERNEST MA ◽  
KEVIN MCILHANY

We present a supersymmetric extension of the standard model where all quark masses and mixing angles except mt are derived as radiative effects induced by the gluino mass. We demonstrate in detail that our model fits well with present data on Vcb and Vub, etc.


2013 ◽  
Vol 87 (5) ◽  
Author(s):  
William A. Ponce ◽  
John D. Gómez ◽  
Richard H. Benavides

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