Advanced search    

Search: authors:"Ivo de Medeiros Varzielas"

10 papers found.
Use AND, OR, NOT, +word, -word, "long phrase", (parentheses) to fine-tune your search.

Fermion masses and mixings and dark matter constraints in a model with radiative seesaw mechanism

Abstract We formulate a predictive model of fermion masses and mixings based on a Δ(27) family symmetry. In the quark sector the model leads to the viable mixing inspired texture where the Cabibbo angle comes from the down quark sector and the other angles come from both up and down quark sectors. In the lepton sector the model generates a predictive structure for charged leptons...

Spontaneous CP violation in multi-Higgs potentials with triplets of Δ(3n 2) and Δ(6n 2)

Motivated by discrete flavour symmetry models, we analyse Spontaneous CP Violation (SCPV) for potentials involving three or six Higgs fields (both electroweak doublets and singlets) which fall into irreducible triplet representations of discrete symmetries belonging to the Δ(3n 2) and Δ(6n 2) series, including A 4, S 4, Δ(27) and Δ(54). For each case, we give the potential and...

Δ(27) family symmetry and neutrino mixing

The observed neutrino mixing, having a near maximal atmospheric neutrino mixing angle and a large solar mixing angle, is close to tri-bi-maximal. This structure may be related to the existence of a discrete non-Abelian family symmetry. In this paper the family symmetry is the non-Abelian discrete group Δ(27), a subgroup of SU(3) with triplet and anti-triplet representations...

Leptogenesis in a Δ(27) × SO(10) SUSY GUT

Although SO(10) Supersymmetric (SUSY) Grand Unification Theories (GUTs) are very attractive for neutrino mass and mixing, it is often quite difficult to achieve successful leptogenesis from the lightest right-handed neutrino N 1 due to the strong relations between neutrino and up-type quark Yukawa couplings. We show that in a realistic model these constraints are relaxed, making...

Clues for flavor from rare lepton and quark decays

Flavor symmetries successfully explain lepton and quark masses and mixings yet it is usually hard to distinguish different models that predict the same mixing angles. Further experimental input could be available, if the agents of flavor breaking are sufficiently low in mass and detectable or if new physics with non-trivial flavor charges is sufficiently low in mass and...

\( {\mathbb{A}}_4 \) symmetry at colliders and in the universe

Two puzzling facts of our time are the observed patterns in the fermion masses and mixings and the existence of non-baryonic dark matter, which are both often associated with extensions of the Standard Model at higher energy scales. In this paper, we consider a solution to these two problems with the flavour symmetry \( {\mathbb{A}}_4\times {\mathrm{\mathbb{Z}}}_2\times {\mathrm...

Leptogenesis in minimal predictive seesaw models

We estimate the Baryon Asymmetry of the Universe (BAU) arising from leptogenesis within a class of minimal predictive seesaw models involving two right-handed neutrinos and simple Yukawa structures with one texture zero. The two right-handed neutrinos are dominantly responsible for the “atmospheric” and “solar” neutrino masses with Yukawa couplings to (ν e...

Towards a complete A4 × SU(5) SUSY GUT

We propose a renormalisable model based on A 4 family symmetry with an SU(5) grand unified theory (GUT) which leads to the minimal supersymmetric standard model (MSSM) with a ℤ9 × ℤ6 symmetry provides the fermion mass hierarchy in both the quark and lepton sectors, while ℤ 4 R symmetry is broken to ℤ 2 R , identified as usual R-parity. Proton decay is highly sup-pressed by these...

Towards predictive flavour models in SUSY SU(5) GUTs with doublet-triplet splitting

We discuss how the double missing partner mechanism solution to the doublet-triplet splitting problem in four-dimensional supersymmetric SU(5) Grand Unified Theories (GUTs) can be combined with predictive models for the quark-lepton Yukawa coupling ratios at the GUT scale. It is argued that towards this goal a second SU(5) breaking Higgs field in the adjoint representation is...