scholarly journals Scotogenic neutrino mass with large $$SU(2)_L$$ multiplet fields

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Nilanjana Kumar ◽  
Takaaki Nomura ◽  
Hiroshi Okada
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Scalar Fields ◽  
Lepton Flavor Violation ◽  
Collider Physics ◽  
Mass Model ◽  
Lepton Flavor ◽  
Flavor Violation

Abstract We construct a scotogenic neutrino mass model introducing large $$SU(2)_L$$SU(2)L multiplet fields without adding an extra symmetry. We have introduced extra scalar fields such as a septet, quintet and quartet where we make the vacuum expectation value of quartet scalar to be zero while septet and quintet develop non-zero ones. Then the neutrino mass is generated at one-loop level by introducing quintet fermion. We analyze the neutrino mass matrix taking constraints from lepton flavor violation into account and discuss collider physics regarding charged fermions from large multiplet fields. We have analysed the production and the decays of the quintet fermions, as well as the discovery reach at 14 TeV and 27 TeV LHC.

scholarly journals Minimal 3-loop neutrino mass models and charged lepton flavor violation

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Ricardo Cepedello ◽  
Martin Hirsch ◽  
Paulina Rocha-Morán ◽  
Avelino Vicente
Keyword(s):  
Neutrino Mass ◽  
Charged Lepton ◽  
Mass Matrix ◽  
Majorana Neutrino ◽  
Lepton Flavor Violation ◽  
Minimal Models ◽  
Yukawa Couplings ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Neutrino Mass Models

Abstract We study charged lepton flavor violation for the three most popular 3-loop Majorana neutrino mass models. We call these models “minimal” since their particle content correspond to the minimal sets for which genuine 3-loop models can be constructed. In all the three minimal models the neutrino mass matrix is proportional to some powers of Standard Model lepton masses, providing additional suppression factors on top of the expected loop suppression. To correctly explain neutrino masses, therefore large Yukawa couplings are needed in these models. We calculate charged lepton flavor violating observables and find that the three minimal models survive the current constraints only in very narrow regions of their parameter spaces.

scholarly journals Muon and electron g − 2 and the origin of the fermion mass hierarchy

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Naoyuki Haba ◽  
Yasuhiro Shimizu ◽  
Toshifumi Yamada
Keyword(s):  
Charged Lepton ◽  
Higgs Sector ◽  
Vacuum Expectation ◽  
Fermion Mass ◽  
Mass Hierarchy ◽  
Lepton Flavor Violation ◽  
Scalar Particles ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Charged Leptons

Abstract We present a model that gives a natural explanation to the charged lepton mass hierarchy and study the contributions to the electron and the muon $g-2$. In the model, we introduce lepton-flavor-dependent $U(1)_F$ symmetry and three additional Higgs doublets with $U(1)_F$ charges, to realize that each generation of charged leptons couples to one of the three additional Higgs doublets. The $U(1)_F$ symmetry is softly broken by $+1$ charges, and the smallness of the soft breaking naturally gives rise to the hierarchy of the Higgs vacuum expectation values, which then accounts for the charged lepton mass hierarchy. Since electron and muon couple to different scalar particles, each scalar contributes to the electron and the muon $g-2$ differently. We survey the space of parameters of the Higgs sector and find that there are sets of parameters that explain the muon $g-2$ discrepancy. On the other hand, we cannot find parameter sets that can explain the $g-2$ discrepancy within 2 $\sigma$. Here, the $U(1)_F$ symmetry suppresses charged lepton flavor violation.

scholarly journals The Low-Scale Approach to Neutrino Masses

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Sofiane M. Boucenna ◽  
Stefano Morisi ◽  
José W. F. Valle
Keyword(s):  
Neutrino Mass ◽  
Cold Dark Matter ◽  
Short Review ◽  
Neutrino Masses ◽  
Lepton Flavor Violation ◽  
Mass Generation ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Phenomenological Potential ◽  
Neutrino Mass Generation

In this short review we revisit the broad landscape of low-scaleSU(3)c⊗SU(2)L⊗U(1)Ymodels of neutrino mass generation, with view on their phenomenological potential. This includes signatures associated to direct neutrino mass messenger production at the LHC, as well as messenger-induced lepton flavor violation processes. We also briefly comment on the presence of WIMP cold dark matter candidates.

scholarly journals lα → 3lβ in minimal R-symmetric supersymmetric Standard Model

2019 ◽  
Vol 35 (04) ◽  
pp. 1950359
Author(s):  
Ke-Sheng Sun ◽  
Jian-Bin Chen ◽  
Hai-Bin Zhang ◽  
Sheng-Kai Cui
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Mass Matrix ◽  
Research Field ◽  
Beyond The Standard Model ◽  
Lepton Flavor Violation ◽  
Decay Channels ◽  
Lepton Flavor ◽  
Flavor Violation ◽  
Theoretical Predictions

Lepton flavor violation decays are channels which may lead to fundamental discoveries in the forthcoming years and this makes it an exciting research field for beyond the Standard Model (SM) searches. In this work, we present an analysis of the lepton flavor violation decays [Formula: see text] in Minimal R-symmetric Supersymmetric Standard Model. The prediction for [Formula: see text] depends on the off-diagonal entries of the slepton mass matrix. The contributions to Wilson coefficients can be classified into Higgs penguins, photon penguins, Z penguins and box diagrams. It shows the contribution from Z penguins dominates the predictions for [Formula: see text], and the contributions from Higgs penguins and box diagrams play different roles in different decay channels. The theoretical predictions for [Formula: see text] can reach the future experimental limits, and the channels are very promising to be observed in near future experiment.

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