scholarly journals Fermion mass hierarchies from modular symmetry

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Simon J.D. King ◽  
Stephen F. King
Keyword(s):  
Standard Model ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Fermion Fields ◽  
Level 3

Abstract We show how quark and lepton mass hierarchies can be reproduced in the framework of modular symmetry. The mechanism is analogous to the Froggatt-Nielsen (FN) mechanism, but without requiring any Abelian symmetry to be introduced, nor any Standard Model (SM) singlet flavon to break it. The modular weights of fermion fields play the role of FN charges, and SM singlet fields with non-zero modular weight called weightons play the role of flavons. We illustrate the mechanism by analysing A4 (modular level 3) models of quark and lepton (including neutrino) masses and mixing, with a single modulus field. We discuss two examples in some detail, both numerically and analytically, showing how both fermion mass and mixing hierarchies emerge from different aspects of the modular symmetry.

scholarly journals DEVELOPING THE FRAMED STANDARD MODEL

2012 ◽  
Vol 27 (17) ◽  
pp. 1250087 ◽  
Author(s):  
MICHAEL J. BAKER ◽  
JOSÉ BORDES ◽  
HONG-MO CHAN ◽  
TSOU SHEUNG TSUN
Keyword(s):  
Standard Model ◽  
Mass Matrix ◽  
Higgs Field ◽  
Fermion Mass ◽  
Ckm Matrix ◽  
Changing Scale ◽  
Rank One ◽  
Distinguishing Features ◽  
Fermion Mass Matrix

The framed standard model (FSM) suggested earlier, which incorporates the Higgs field and three fermion generations as part of the framed gauge theory (FGT) structure, is here developed further to show that it gives both quarks and leptons hierarchical masses and mixing matrices akin to what is experimentally observed. Among its many distinguishing features which lead to the above results are (i) the vacuum is degenerate under a global su(3) symmetry which plays the role of fermion generations, (ii) the fermion mass matrix is "universal," rank-one and rotates (changes its orientation in generation space) with changing scale μ, (iii) the metric in generation space is scale-dependent too, and in general nonflat, (iv) the theta-angle term in the quantum chromodynamics (QCD) action of topological origin gets transformed into the CP-violating phase of the Cabibbo–Kobayashi–Maskawa (CKM) matrix for quarks, thus offering at the same time a solution to the strong CP problem.

scholarly journals LEPTOGENESIS AND LHC PHYSICS WITH TYPE III SEE-SAW

2011 ◽  
Vol 01 ◽  
pp. 18-27 ◽  
Author(s):  
SHAO-LONG CHEN ◽  
XIAO-GANG HE
Keyword(s):  
Standard Model ◽  
Charged Lepton ◽  
Baryon Asymmetry ◽  
Neutrino Masses ◽  
Neutral Particles ◽  
Type Iii ◽  
Lhc Physics

The See-Saw mechanism provides a nice way to explain why neutrino masses are so much lighter than their charged lepton partners. It also provides a nice way to explain baryon asymmetry in our universe via the leptogenesis mechanism. In this talk we review leptogenesis and LHC physics in a See-Saw model proposed in 1989, now termed the Type III See-Saw model. In this model, SU(2)L triplet leptons are introduced with the neutral particles of the triplets playing the role of See-Saw. The triplet leptons have charged partners with standard model gauge interactions resulting in many new features. The gauge interactions of these particles make it easier for leptognesis with low masses, as low as a TeV is possible. The gauge interactions also make the production and detection of triplet leptons at LHC possible. The See-Saw mechanism and leptogenesis due to Type III See-Saw may be tested at LHC.

scholarly journals MASS GENERATION AND THE DYNAMICAL ROLE OF THE KATOPTRON GROUP

2001 ◽  
Vol 16 (02) ◽  
pp. 53-61 ◽  
Author(s):  
GEORGE TRIANTAPHYLLOU
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Higgs Sector ◽  
Viable Alternative ◽  
Fermion Mass ◽  
Main Function ◽  
Mass Generation ◽  
The Standard Model ◽  
Gauge Interaction

Heavy mirror fermions along with a new strong gauge interaction capable of breaking the electroweak gauge symmetry dynamically were recently introduced under the name of katoptrons. Their main function is to provide a viable alternative to the Standard-Model Higgs sector. In such a framework, ordinary fermions acquire masses after the breaking of the strong katoptron group which allows mixing with their katoptron partners. The purpose of this letter is to study the elementary-scalars-free mechanism responsible for this breaking and its implications for the fermion mass hierarchies.

scholarly journals EXPLORING FRAMED GAUGE THEORY AS BASIS FOR PHYSICAL MODELS

2012 ◽  
Vol 27 (02) ◽  
pp. 1230002 ◽  
Author(s):  
HONG-MO CHAN ◽  
SHEUNG TSUN TSOU
Keyword(s):  
Standard Model ◽  
Higgs Field ◽  
Internal Symmetry ◽  
Physical Models ◽  
Theoretical Structure ◽  
Fermion Fields ◽  
The Standard Model ◽  
Mixing Patterns ◽  
Symmetry Space

It is shown that by introducing as dynamical variables in the formulation of gauge theories the frame vectors (or vielbeins) in internal symmetry space, in addition to the standard gauge boson and matter fermion fields, one obtains: (i) for the su(2) ×u(1) symmetry, the standard electroweak theory with the Higgs field thrown in as part of the framed gauge theoretical structure, (ii) for the su(3) ×su(2) ×u(1) symmetry, a "framed standard model" with, apart from the Higgs field as before, a global su(3) symmetry to play the role of fermion generations, plus some other properties which are shown elsewhere to give to both quarks and leptons hierarchical mass and mixing patterns similar to those experimentally observed. Besides, the "framing" of the standard model as such has brought the particle theory closer in structure to the theory of gravity where vierbeins have long figured as dynamical variables. Although most of the results have already been reported before, time and hindsight have allowed their presentation in this review to be made more transparent and succint.

scholarly journals POSSIBLE TEXTURES OF THE FERMION MASS MATRICES

2011 ◽  
Vol 26 (18) ◽  
pp. 2973-2995 ◽  
Author(s):  
MANMOHAN GUPTA ◽  
GULSHEEN AHUJA
Keyword(s):  
Quark Mass ◽  
Fermion Mass ◽  
Neutrino Masses ◽  
Fermion Masses ◽  
Mass Matrices

Texture specific fermion mass matrices have played an important role in understanding several features of fermion masses and mixings. In the present work, we have given an overview of all possible cases of Fritzsch-like as well as non-Fritzsch-like texture 6 and 5 zero fermion mass matrices. Further, for the case of texture 4 zero Fritzsch-like quark mass matrices, the issue of the hierarchy of the elements of the mass matrices and the role of their phases have been discussed. Furthermore, the case of texture 4 zero Fritzsch-like lepton mass matrices has also been discussed with an emphasis on the hierarchy of neutrino masses for both Majorana and Dirac neutrinos.

scholarly journals Role of Bc+→Bs,d(*)ℓ¯νℓ in the Standard Model and in the search for BSM signals

2021 ◽  
Vol 103 (7) ◽  
Author(s):  
Pietro Colangelo ◽  
Fulvia De Fazio ◽  
Francesco Loparco
Keyword(s):  
Standard Model ◽  
The Standard Model

scholarly journals Philosophers in research ethics committees—what do they think they’re doing? An empirical-ethical analysis

2021 ◽  
Author(s):  
Charlotte Gauckler
Keyword(s):  
Research Ethics ◽  
Applied Ethics ◽  
Ethics Committees ◽  
Research Ethics Committees ◽  
Structured Interviews ◽  
Discussion Section ◽  
Philosophical Perspective ◽  
Level 3 ◽  
Practical Level

AbstractResearch ethics committees in Germany usually don’t have philosophers as members and if so, only contingently, not provided for by statute. This is interesting from a philosophical perspective, assuming that ethics is a discipline of philosophy. It prompts the question what role philosophers play in those committees they can be found in. Eight qualitative semi-structured interviews were conducted to explore the self-perception of philosophers regarding their contribution to research ethics committees. The results show that the participants generally don’t view themselves as ethics experts. They are rather unanimous on the competencies they think they contribute to the committee but not as to whether those are philosophical competencies or applied ethical ones. In some cases they don’t see a big difference between their role and the role of the jurist member. In the discussion section of this paper I bring up three topics, prompted by the interviews, that need to be addressed: (1) I argue that the interviewees’ unwillingness to call themselves ethics experts might have to do with a too narrow understanding of ethics expertise. (2) I argue that the disagreement among the interviewees concerning the relationship between moral philosophy and applied ethics might be explained on a theoretical or on a practical level. (3) I argue that there is some lack of clarity concerning the relationship between ethics and law in research ethics committees and that further work needs to be done here. All three topics, I conclude, need further investigation.

scholarly journals Dark matter candidates in a type-II radiative neutrino mass model

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Roberto A. Lineros ◽  
Mathias Pierre
Keyword(s):  
Dark Matter ◽  
Neutral Particle ◽  
Matter Density ◽  
Indirect Detection ◽  
Dark Matter Candidate ◽  
Neutrino Masses ◽  
Type Ii ◽  
Mass Model ◽  
Direct And Indirect Detection

Abstract We explore the connection between Dark Matter and neutrinos in a model inspired by radiative Type-II seessaw and scotogenic scenarios. In our model, we introduce new electroweakly charged states (scalars and a vector-like fermion) and impose a discrete ℤ2 symmetry. Neutrino masses are generated at the loop level and the lightest ℤ2-odd neutral particle is stable and it can play the role of a Dark Matter candidate. We perform a numerical analysis of the model showing that neutrino masses and flavour structure can be reproduced in addition to the correct dark matter density, with viable DM masses from 700 GeV to 30 TeV. We explore direct and indirect detection signatures and show interesting detection prospects by CTA, Darwin and KM3Net and highlight the complementarity between these observables.

scholarly journals Neutrino masses along with fermion mass hierarchy

2012 ◽  
Vol 85 (1) ◽  
Author(s):  
Dilip Kumar Ghosh ◽  
R. S. Hundi
Keyword(s):  
Fermion Mass ◽  
Neutrino Masses ◽  
Mass Hierarchy

TeV Scale B – L Phenomenology at LHC

2007 ◽  
Vol 22 (31) ◽  
pp. 5889-5908 ◽  
Author(s):  
M. Abbas ◽  
W. Emam ◽  
S. Khalil ◽  
M. Shalaby
Keyword(s):  
Standard Model ◽  
Gauge Boson ◽  
Cross Sections ◽  
Branching Ratios ◽  
Higgs Production ◽  
Neutrino Masses ◽  
Natural Explanation ◽  
The Standard Model ◽  
The Cross

We present the phenomenology of the low scale U(1)B–L extension of the standard model and its implications at LHC. We show that this model provides a natural explanation for the presence of three right-handed neutrinos and can naturally account the observed neutrino masses and mixing. We study the decay and production of the extra gauge boson and the SM singlet scalar (heavy Higgs) predicted in this type of models. We find that the cross sections of the SM-like Higgs production are reduced by ~ 20% – 30%, while its decay branching ratios remain intact. The extra Higgs has relatively small cross sections and the branching ratios of Z′ → l+l− are of order ~ 20% compared to ~ 3% of the SM results.

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