scholarly journals The ScotoSinglet Model: a scalar singlet extension of the Scotogenic Model

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Ankit Beniwal ◽  
Juan Herrero-García ◽  
Nicholas Leerdam ◽  
Martin White ◽  
Anthony G. Williams
Keyword(s):  
Parameter Space ◽  
Direct Detection ◽  
Neutrino Masses ◽  
Minimal Models ◽  
Flavour Violation ◽  
The One ◽  
Relic Abundance ◽  
Electroweak Precision ◽  
Scalar Singlet ◽  
Lepton Flavour

Abstract The Scotogenic Model is one of the most minimal models to account for both neutrino masses and dark matter (DM). In this model, neutrino masses are generated at the one-loop level, and in principle, both the lightest fermion singlet and the lightest neutral component of the scalar doublet can be viable DM candidates. However, the correct DM relic abundance can only be obtained in somewhat small regions of the parameter space, as there are strong constraints stemming from lepton flavour violation, neutrino masses, electroweak precision tests and direct detection. For the case of scalar DM, a sufficiently large lepton-number-violating coupling is required, whereas for fermionic DM, coannihilations are typically necessary. In this work, we study how the new scalar singlet modifies the phenomenology of the Scotogenic Model, particularly in the case of scalar DM. We find that the new singlet modifies both the phenomenology of neutrino masses and scalar DM, and opens up a large portion of the parameter space of the original model.

scholarly journals Whac-a-constraint with anomaly-free dark matter models

2019 ◽  
Vol 6 (2) ◽  
Author(s):  
Sonia El Hedri ◽  
Karl Nordström
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Parameter Space ◽  
Direct Detection ◽  
Simplified Model ◽  
Dark Matter Candidate ◽  
Minimal Models ◽  
Simplified Models ◽  
The Standard Model ◽  
The One

Theories where a fermionic dark matter candidate interacts with the Standard Model through a vector mediator are often studied using minimal models, which are not necessarily anomaly-free. In fact, minimal anomaly-free simplified models are usually strongly constrained by either direct detection experiments or collider searches for dilepton resonances. In this paper, we study the phenomenology of models with a fermionic dark matter candidate that couples axially to a leptophobic vector mediator. Canceling anomalies in these models requires considerably enlarging their field content. For an example minimal scenario we show that the additional fields lead to a potentially much richer phenomenology than the one predicted by the original simplified model. In particular collider searches for pair-produced neutralinos and charginos can be more sensitive than traditional monojet searches in thermally motivated parts of the parameter space where the mediator is outside the reach of current searches.

scholarly journals The singly-charged scalar singlet as the origin of neutrino masses

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Tobias Felkl ◽  
Juan Herrero-García ◽  
Michael A. Schmidt
Keyword(s):  
Mass Matrix ◽  
Boson Mass ◽  
Neutrino Masses ◽  
Charged Scalar ◽  
Yukawa Couplings ◽  
Left Handed ◽  
Flavour Violation ◽  
Singly Charged ◽  
Charged Lepton Sector ◽  
Scalar Singlet

Abstract We consider the generation of neutrino masses via a singly-charged scalar singlet. Under general assumptions we identify two distinct structures for the neutrino mass matrix. This yields a constraint for the antisymmetric Yukawa coupling of the singly-charged scalar singlet to two left-handed lepton doublets, irrespective of how the breaking of lepton-number conservation is achieved. The constraint disfavours large hierarchies among the Yukawa couplings. We study the implications for the phenomenology of lepton-flavour universality, measurements of the W-boson mass, flavour violation in the charged-lepton sector and decays of the singly-charged scalar singlet. We also discuss the parameter space that can address the Cabibbo Angle Anomaly.

scholarly journals Parametrization of the Yukawa matrix in the scotogenic model and single-zero textures of the neutrino mass matrix

2019 ◽  
Vol 34 (19) ◽  
pp. 1950098 ◽  
Author(s):  
Teruyuki Kitabayashi
Keyword(s):  
Neutrino Mass ◽  
Mass Matrix ◽  
Branching Ratio ◽  
Neutrino Mass Matrix ◽  
Neutrino Masses ◽  
Neutrino Sector ◽  
The One ◽  
Relic Abundance ◽  
Analytical Expressions ◽  
Data Group

As the first topic, we propose a new parametrization of the complex Yukawa matrix in the scotogenic model. The new parametrization is compatible with the particle data group parametrization of the neutrino sector. Some analytical expressions for the neutrino masses with the new parametrization are shown. As the second topic, we consider the phenomenology of the scotogenic model with the one-zero-textures of the neutrino flavor mass matrix. One of the six patterns of the neutrino mass matrix is favorable for the real Yukawa matrix. On the other hand, for the complex Yukawa matrix, five of the six patterns are compatible with observations of the neutrino oscillations, dark matter relic abundance and branching ratio of the [Formula: see text] process.

scholarly journals Neutrino masses at LHC: minimal lepton flavour violation in Type-III see-saw

2011 ◽  
Vol 2011 (12) ◽  
Author(s):  
O. J. P. Éboli ◽  
J. Gonzalez-Fraile ◽  
M. C. Gonzalez-Garcia
Keyword(s):  
Neutrino Masses ◽  
Type Iii ◽  
Lepton Flavour Violation ◽  
Flavour Violation ◽  
Lepton Flavour

scholarly journals Confronting grand unification with lepton flavour violation, dark matter and LHC data

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
J. Ellis ◽  
M. E. Gómez ◽  
S. Lola ◽  
R. Ruiz de Austri ◽  
Q. Shafi
Keyword(s):  
Dark Matter ◽  
Group Symmetry ◽  
Neutrino Masses ◽  
High Input ◽  
Lepton Flavour Violation ◽  
Flavour Violation ◽  
Soft Supersymmetry Breaking ◽  
Good Detection ◽  
Lepton Flavour

Abstract We explore possible signatures for charged lepton flavour violation (LFV), sparticle discovery at the LHC and dark matter (DM) searches in grand unified theories (GUTs) based on SU(5), flipped SU(5) (FSU(5)) and SU(4)c×SU(2)L×SU(2)R (4-2-2). We assume that soft supersymmetry-breaking terms preserve the group symmetry at some high input scale, and focus on the non-universal effects on different matter representations generated by gauge interactions at lower scales, as well as the charged LFV induced in Type-1 see-saw models of neutrino masses. We identify the different mechanisms that control the relic DM density in the various GUT models, and contrast their LFV and LHC signatures. The SU(5) and 4-2-2 models offer good detection prospects both at the LHC and in LFV searches, though with different LSP compositions, and the SU(5) and FSU(5) models offer LFV within the current reach. The 4-2-2 model allows chargino and gluino coannihilations with neutralinos, and the former offer good detection prospects for both the LHC and LFV, while gluino coannihilations lead to lower LFV rates. Our results indicate that LFV is a powerful tool that complements LHC and DM searches, providing significant insights into the sparticle spectra and neutrino mass parameters in different models.

scholarly journals SUSY INTO DARKNESS: HEAVY SCALARS IN THE CMSSM

2013 ◽  
Vol 28 (15) ◽  
pp. 1350061 ◽  
Author(s):  
VAN E. MAYES
Keyword(s):  
Dark Matter ◽  
Parameter Space ◽  
Cross Sections ◽  
Higgs Mass ◽  
Cold Dark Matter ◽  
Direct Detection ◽  
Percent Level ◽  
Relic Density ◽  
The One ◽  
Near Future

A survey of the mSUGRA/CMSSM parameter space is presented. The viable regions of the parameter space which satisfy standard experimental constraints are identified and discussed. These constraints include a 124–127 GeV mass for the lightest CP-even Higgs and the correct relic density for cold dark matter. The superpartner spectra corresponding to these regions fall within the well-known hyperbolic branch and are found to possess sub-TeV neutralinos and charginos, with mixed Bino/Higgsino LSP's with 200–800 GeV masses. In addition, the models possess ~3–4 TeV gluino masses and heavy squarks and sleptons with masses [Formula: see text]. Spectra with a Higgs mass mh≅125 GeV and a relic density 0.105 ≤ Ωχ0h2≤ 0.123 are found to require EWFT at around the one-percent level, while those spectra with a much lower relic density require EWFT of only a few percent. Moreover, the spin-independent neutralino–proton direct detection cross-sections are found to be below or within the XENON100 2σ limit and should be experimentally accessible now or in the near future. Finally, it is pointed out that the supersymmetry breaking soft terms corresponding to these regions of the mSUGRA/CMSSM parameter space (m0∝ m1/2with [Formula: see text] and A0= -m1/2) may be obtained from general flux-induced soft terms in Type IIB flux compactifications with D3 branes.

scholarly journals Effective-field theories for charged lepton flavour violation

2018 ◽  
Vol 179 ◽  
pp. 01019
Author(s):  
Giovanni Marco Pruna
Keyword(s):  
Field Theory ◽  
Effective Field Theories ◽  
Parameter Space ◽  
Effective Field Theory ◽  
Charged Lepton ◽  
Effective Field ◽  
Field Theories ◽  
The Status ◽  
Flavour Violation ◽  
Lepton Flavour

These proceedings review the status of present and future bounds on muonic lepton flavour violating transitions in the context of an effective-field theory defined below the electroweak scale. A specific focus is set on the phenomenology of μ → eγ, μ → 3e transitions and coherent μ → e nuclear conversion in the light of current and future experiments. Once the experimental limits are recast into bounds at higher scales, it is shown that the interplay between the various experiments is crucial to cover all corners of the parameter space.

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