Related papers: Are Four-Fermion Operators Relevant for the Fermio…
We study extensions of the standard model with a strongly coupled fourth generation. This occurs in models where electroweak symmetry breaking is triggered by the condensation of at least some of the fourth-generation fermions. With focus…
Precision measurements of high energy top quarks at the LHC constitute a powerful probe of new physics. We study the effect of four fermion operators involving two tops and two light quarks on the high energy tail of the $t\bar t$ invariant…
A new approach for deducing the theory of fermion masses at the scale of grand unification is proposed. Combining SO(10) grand unification, family symmetries and supersymmetry with a systematic operator analysis, the minimal set of fermion…
Asymmetry measurements in $e^+e^-\to\tau^+\tau^-$ constitute a promising avenue to obtain competitive constraints on the $\tau$ dipole moments, the anomalous magnetic moment $a_\tau$ and the electric dipole moment $d_\tau$, especially, once…
A phenomenological theory of fermion masses and mixings is constructed within the framework of a four- family symmetry. It is found that the most favored set of relevant CKM elements are $|V_{us}|\approx 0.222$, $|V_{cb}|\approx 0.044$,…
We present a novel mechanism for generating gauge-invariant fermion masses through global anomalies at the three loop level. In a gauge theory, global anomalies are triggered by the possible existence of scalar or pseudoscalar states and…
The aim of this thesis is to determine possible interactions between the Standard Model with right-chiral neutrinos and a sector of dark matter composed of a real scalar, left- and right-chiral fermion and a vector particle, which are…
Several proposals for dynamical electroweak symmetry breaking and fermion mass generation involve strong gauge interactions with a characteristic scale of a few hundred GeV. The detection of the glueballs which should occur in such models…
This paper presents a formulation of lattice fermions applicable to all quark masses, large and small. We incorporate interactions from previous light-fermion and heavy-fermion methods, and thus ensure a smooth connection to these limiting…
Recently a new dynamical symmetry breaking model of electroweak interactions was proposed based on interacting fermions. Two fermions of different SU(2) representations form a symmetry breaking condensate and generate the lepton and quark…
We consider the generation of fermion masses in an emergent model of electroweak symmetry breaking with composite $W,Z$ gauge bosons. A universal bulk fermion profile in a warped extra dimension is used for all fermion flavors. Electroweak…
Assuming the small entries in the mass matrices are produced by fermion-scalar loops, we calculate the anomalous dipole moments of the leptons and quarks. The top quark appears in all the loops as the mass seed. When comparing the results…
There is growing interest in the development of a muon collider that would make it possible to produce lepton collisions at energies of several TeV. Among others, there can be significant contributions to electroweak gauge boson, Higgs…
The chirality-flipping operators of light fermions are currently poorly constrained by experimental analyses due to the lack of interference with Standard Model (SM) amplitudes in traditional observables. In this work, we propose to…
Given the most general Lorentz invariant four-fermion effective interaction possible for two neutrinos and two charged fermions, whether quarks or leptons, all possible 2-to-2 processes involving two neutrinos, whether Dirac or Majorana…
We present calculations of matrix elements of 4-quark operators in the pion and in the nucleon extracted from quenched Monte Carlo simulations at beta = 6.0 using Wilson fermions. These operators are relevant for higher-twist effects. We…
We propose a theoretical framework for evaluating the effect of four-fermion operators on the mass of composite particles in confining strongly-coupled gauge theories. The confining sector is modelled by a non-local Nambu-Jona Lasinio…
Fermion masses and mixing, both in the quark and leptonic sector, are discussed within the approach to the Yukawa puzzle proposed by Arkani-Hamed and Schmaltz. In the quark sector we have shown that at least two extra dimensions are…
The renormalization of the most general dimension-six four-fermion operators without power subtractions is studied at one loop in lattice perturbation theory using overlap fermions. As expected, operators with different chirality do not mix…
Different approaches to the fermion mass problem are reviewed. We illustrate these approaches by summarizing recent developments in models of quark and lepton mass matrices. Dynamical calculations of the top quark mass are discussed, based…