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We build upon a simple $U(2)_F$ model of flavor, in which all fermion masses and mixing hierarchies arise from powers of two small parameters controlling $U(2)_F$ breaking. In the original formulation, an isomorphism to the discrete…

High Energy Physics - Phenomenology · Physics 2026-02-24 A. Giarnetti , S. Marciano , D. Meloni , M. Rettaroli

We propose a new model of leptons and quarks based on the discrete flavor symmetry $T'$, the double covering of $A_4$, in which the hierarchies of charged fermion masses and the mildness of neutrino masses are responsible for Higgs scalars.…

High Energy Physics - Phenomenology · Physics 2013-07-17 Y. H. Ahn

Numerical correlations between fermion masses and mixings could indicate the presence of a flavor symmetry at high energies. In general, the search for these correlations using low-energy data requires an estimate of leading-log radiative…

High Energy Physics - Phenomenology · Physics 2009-10-28 J. A. Aguilar-Saavedra , M. Masip

The smallness of fermion masses and mixing angles has recently been been attributed to approximate global $U(1)$ symmetries, one for each fermion type. The parameters associated with these symmetry breakings are estimated here directly from…

High Energy Physics - Phenomenology · Physics 2009-12-30 Lawrence Hall , Steven Weinberg

Little Higgs Models have been introduced to resolve the fine-tuning problems associated with the stability of the electroweak scale and the constraints imposed by the precision electroweak analysis of experiments testing the Standard Model…

High Energy Physics - Phenomenology · Physics 2017-08-23 William A. Bardeen

We propose a simple non-supersymmetric lepton flavor model with $A_4$ symmetry. The $A_4$ group is a minimal one which includes triplet irreducible representation. We introduce three Higgs doublets which are assigned as triplet of the $A_4$…

High Energy Physics - Phenomenology · Physics 2023-06-28 Yukimura Izawa , Yusuke Shimizu , Hironori Takei

The dipole moments of the leptons and quarks are matrices in flavor space, which can potentially reveal as much about the flavor structure of the theory as do the mass matrices. The off-diagonal elements of the dipole matrices lead to…

High Energy Physics - Phenomenology · Physics 2014-11-17 K. S. Babu , S. M. Barr , Ilja Dorsner

Current data implies three simple forms of the neutrino mass matrix, each corresponding to the conservation of a non-standard lepton charge. While models based on L_e and L_e - L_mu - L_tau are well-known, little attention has been paid to…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. Rodejohann , M. A. Schmidt

We present a model of the lepton masses and flavor mixing based on the discrete group $S_4 \times Z_2$. In this model, all the charged leptons and neutrinos are assigned to the $3_\alpha$ representation of $S_4$ in the Yamanouchi bases. The…

High Energy Physics - Phenomenology · Physics 2008-11-26 He Zhang

A bottom-up approach has been adopted to identify a flavour model that agrees with present experimental measurements. The charged fermion mass hierarchies suggest that only the top Yukawa term should be present at the renormalisable level.…

High Energy Physics - Phenomenology · Physics 2020-09-22 Luca Merlo

We present the results of an extensive analysis of flavour physics in both quark and lepton sectors, in the Littlest Higgs model with T-parity (LHT). In the quark sector, we identify some interesting scenarios for new mirror quark masses…

High Energy Physics - Phenomenology · Physics 2011-03-23 Cecilia Tarantino

The renormalization effect on a specific ansatz of lepton mass matrices, arising naturally from the breaking of flavor democracy for charged leptons and that of mass degeneracy for light neutrinos, is studied from a superhigh energy scale…

High Energy Physics - Phenomenology · Physics 2009-10-31 Zhi-zhong Xing

Theoretical aspects of neutrino physics are reviewed, with emphasis on possible explanations of the smallness of neutrino masses and of the peculiar mixing pattern observed in the lepton sector. Some theoretically motivated frameworks, such…

High Energy Physics - Phenomenology · Physics 2008-08-07 Ferruccio Feruglio , Claudia Hagedorn , Yin Lin , Luca Merlo

We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields,…

High Energy Physics - Phenomenology · Physics 2016-09-07 Prateek Agrawal , Zackaria Chacko , Elaine C. F. S. Fortes , Can Kilic

We derive the lower bound on absolute scale of lightest neutrino mass for normal hierarchy and inverted hierarchy pattern of light neutrinos by studying the new physics contributions to charged lepton flavour violating decays and…

High Energy Physics - Phenomenology · Physics 2022-07-25 Prativa Pritimita , Urjit A. Yajnik , Nitali Dash , Sudhanwa Patra

We describe a model of quarks which identifies the large global symmetries of little Higgs models with the global flavor symmetries that arise in a deconstruction of the extra-dimensional 'topological insulator' model of flavor. The…

High Energy Physics - Phenomenology · Physics 2013-08-09 Sichun Sun , David B. Kaplan , Ann E. Nelson

Considering the hierarchical structure of fermionic masses and the fermionic flavor mixing puzzles in the Standard Model, we propose to relate them by the see-saw mechanism, i.e. only the third generation of quarks and charged leptons…

High Energy Physics - Phenomenology · Physics 2024-05-06 Jin-Lei Yang , Hai-Bin Zhang , Tai-Fu Feng

We study the implications of an approximate $U(2)^5$ flavor symmetry at the TeV scale, under the assumption of new physics predominantly coupled to the third-generation fermions, focusing on the breaking of the $U(2)_\ell$ subgroup…

High Energy Physics - Phenomenology · Physics 2025-11-21 Sebastiano Covone , Pol Morell , Arianna Tinari

Recent atmospheric and solar neutrino experiments suggest that neutrinos have small but nonzero masses. They further suggest that mass eigenvalues have certain degree of hierarchical structures, and also some mixing angles are near-maximal…

High Energy Physics - Phenomenology · Physics 2007-05-23 Kiwoon Choi

To search for possible textures of lepton mass matrices, we systematically examine flavor mixing structures which can lead to large lepton mixing angles. We find out 37 mixing patterns are consistent with experimental data, taking into…

High Energy Physics - Phenomenology · Physics 2009-11-07 N. Haba , J. Sato , M. Tanimoto , K. Yoshioka