The simplest models of radiative neutrino mass

2014 ◽  
Vol 29 (10) ◽  
pp. 1450064 ◽  
Author(s):  
Sandy S. C. Law ◽  
Kristian L. McDonald
Keyword(s):  
Neutrino Mass ◽  
Ad Hoc ◽  
Charged Scalar ◽  
New Model ◽  
Real Scalar ◽  
Neutrino Mass Models ◽  
Doubly Charged ◽  
Simple Models

The complexity of radiative neutrino-mass models can be judged by: (i) whether they require the imposition of ad hoc symmetries, (ii) the number of new multiplets they introduce and (iii) the number of arbitrary parameters that appear. Considering models that do not employ new symmetries, the simplest models have two new multiplets and a minimal number of new parameters. With this in mind, we search for the simplest models of radiative neutrino mass. We are led to two models, containing a real scalar triplet and a charged scalar doublet (respectively), in addition to the charged singlet scalar considered by Zee [h+~(1, 1, 2)]. These models are essentially simplified versions of the Zee model and appear to be the simplest models of radiative neutrino mass. However, despite successfully generating nonzero masses, present-day data is sufficient to rule these simple models out. The Zee and Zee–Babu models therefore remain as the simplest viable models. Moving beyond the minimal cases, we find a new model of two-loop masses that employs the charged doublet Φ~(1, 2, 3) and the doubly-charged scalar k++~(1, 1, 4). This is the sole remaining model that employs only three new noncolored multiplets.

scholarly journals Detecting long-lived multi-charged particles in neutrino mass models with MoEDAL

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
Martin Hirsch ◽  
Rafał Masełek ◽  
Kazuki Sakurai
Keyword(s):  
Neutrino Mass ◽  
Electric Charge ◽  
Production Cross ◽  
Charged Particles ◽  
New Physics ◽  
Independent Study ◽  
Strong Interactions ◽  
Mass Generation ◽  
Charged Scalar ◽  
Neutrino Mass Models

AbstractA certain class of neutrino mass models predicts long-lived particles whose electric charge is four or three times larger than that of protons. Such particles, if they are light enough, may be produced at the LHC and detected. We investigate the possibility of observing those long-lived multi-charged particles with the MoEDAL detector, which is sensitive to long-lived particles with low velocities ($$\beta $$ β ) and a large electric charge (Z) with $$\Theta \equiv \beta /Z \lesssim 0.15$$ Θ ≡ β / Z ≲ 0.15 . We demonstrate that multi-charged scalar particles with a large Z give three-fold advantage for MoEDAL; reduction of $$\Theta $$ Θ due to strong interactions with the detector, and enhancement of the photon-fusion process, which not only increases the production cross-section but also lowers the average production velocity, reducing $$\Theta $$ Θ further. To demonstrate the performance of MoEDAL on multi-charged long-lived particles, two concrete neutrino mass models are studied. In the first model, the new physics sector is non-coloured and contains long-lived particles with electric charges 2, 3 and 4. A model-independent study finds MoEDAL can expect more than 1 signal event at the HL-LHC ($$L = 300$$ L = 300 $$\hbox {fb}^{-1}$$ fb - 1 ) if these particles are lighter than 600, 1100 and 1430 GeV, respectively. These compare with the current ATLAS limits 650, 780 and 920 GeV for $$L = 36$$ L = 36 $$\hbox {fb}^{-1}$$ fb - 1 . The second model has a coloured new physics sector, which possesses long-lived particles with electric charges 4/3, 7/3 and 10/3. The corresponding MoEDAL’s mass reaches at the HL-LHC are 1400, 1650 and 1800 GeV, respectively, which compare with the current CMS limits 1450, 1480 and 1510 GeV for $$L = 36$$ L = 36 $$\hbox {fb}^{-1}$$ fb - 1 . In a model-specific study we explore the parameter space of neutrino mass generation models and identify the regions that can be probed with MoEDAL at the end of Run-3 and the High-Luminosity LHC.

scholarly journals Observable proton decay in flipped SU(5)

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Maria Mehmood ◽  
Mansoor Ur Rehman ◽  
Qaisar Shafi
Keyword(s):  
Neutrino Mass ◽  
Gauge Coupling ◽  
Proton Decay ◽  
Type I ◽  
Mass Model ◽  
Intermediate Scale ◽  
Decay Channels ◽  
Proton Lifetime ◽  
Hybrid Inflation ◽  
Neutrino Mass Models

Abstract We explore proton decay in a class of realistic supersymmetric flipped SU(5) models supplemented by a U(1)R symmetry which plays an essential role in implementing hybrid inflation. Two distinct neutrino mass models, based on inverse seesaw and type I seesaw, are identified, with the latter arising from the breaking of U(1)R by nonrenormalizable superpotential terms. Depending on the neutrino mass model an appropriate set of intermediate scale color triplets from the Higgs superfields play a key role in proton decay channels that include p → (e+, μ+) π0, p → (e+, μ+) K0, p →$$ \overline{v}{\pi}^{+} $$ v ¯ π + , and p →$$ \overline{v}{K}^{+} $$ v ¯ K + . We identify regions of the parameter space that yield proton lifetime estimates which are testable at Hyper-Kamiokande and other next generation experiments. We discuss how gauge coupling unification in the presence of intermediate scale particles is realized, and a Z4 symmetry is utilized to show how such intermediate scales can arise in flipped SU(5). Finally, we compare our predictions for proton decay with previous work based on SU(5) and flipped SU(5).

scholarly journals Relaxing cosmological neutrino mass bounds with unstable neutrinos

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Miguel Escudero ◽  
Jacobo Lopez-Pavon ◽  
Nuria Rius ◽  
Stefan Sandner
Keyword(s):  
Neutrino Mass ◽  
Particle Physics ◽  
Goldstone Boson ◽  
Mass Scale ◽  
Simple Extension ◽  
Type I ◽  
Mass Generation ◽  
Age Of The Universe ◽  
Neutrino Mass Models ◽  
The Right

Abstract At present, cosmological observations set the most stringent bound on the neutrino mass scale. Within the standard cosmological model (ΛCDM), the Planck collaboration reports ∑mv< 0.12 eV at 95 % CL. This bound, taken at face value, excludes many neutrino mass models. However, unstable neutrinos, with lifetimes shorter than the age of the universe τν ≲ tU, represent a particle physics avenue to relax this constraint. Motivated by this fact, we present a taxonomy of neutrino decay modes, categorizing them in terms of particle content and final decay products. Taking into account the relevant phenomenological bounds, our analysis shows that 2-body decaying neutrinos into BSM particles are a promising option to relax cosmological neutrino mass bounds. We then build a simple extension of the type I seesaw scenario by adding one sterile state ν4 and a Goldstone boson ϕ, in which νi→ ν4ϕ decays can loosen the neutrino mass bounds up to ∑mv ∼ 1 eV, without spoiling the light neutrino mass generation mechanism. Remarkably, this is possible for a large range of the right-handed neutrino masses, from the electroweak up to the GUT scale. We successfully implement this idea in the context of minimal neutrino mass models based on a U(1)μ−τ flavor symmetry, which are otherwise in tension with the current bound on ∑mv.

scholarly journals Exploding operators for Majorana neutrino masses and beyond

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
John Gargalionis ◽  
Raymond R. Volkas
Keyword(s):  
Neutrino Mass ◽  
Model Building ◽  
Dominant Role ◽  
New Physics ◽  
Majorana Neutrino ◽  
Effective Field ◽  
Tree Level ◽  
Mass Generation ◽  
Neutrino Mass Models ◽  
Almost All

Abstract Building UV completions of lepton-number-violating effective operators has proved to be a useful way of studying and classifying models of Majorana neutrino mass. In this paper we describe and implement an algorithm that systematises this model-building procedure. We use the algorithm to generate computational representations of all of the tree-level completions of the operators up to and including mass-dimension 11. Almost all of these correspond to models of radiative neutrino mass. Our work includes operators involving derivatives, updated estimates for the bounds on the new-physics scale associated with each operator, an analysis of various features of the models, and a look at some examples. We find that a number of operators do not admit any completions not also generating lower-dimensional operators or larger contributions to the neutrino mass, ruling them out as playing a dominant role in the neutrino-mass generation. Additionally, we show that there are at most five models containing three or fewer exotic multiplets that predict new physics that must lie below 100 TeV. Accompanying this work we also make available a searchable database containing all of our results and the code used to find the completions. We emphasise that our methods extend beyond the study of neutrino-mass models, and may be useful for generating completions of high-dimensional operators in other effective field theories. Example code: ref. [37].

scholarly journals Discriminating leptonic Yukawa interactions with doubly charged scalar at the ILC

2018 ◽  
Vol 929 ◽  
pp. 193-206 ◽  
Author(s):  
Takaaki Nomura ◽  
Hiroshi Okada ◽  
Hiroshi Yokoya
Keyword(s):  
Charged Scalar ◽  
Doubly Charged

Construction of neutrino models with non-vanishing θ13 and leptogenesis

2015 ◽  
Vol 93 (12) ◽  
pp. 1561-1565
Author(s):  
Ng. K. Francis
Keyword(s):  
Neutrino Mass ◽  
Big Bang ◽  
Baryon Asymmetry ◽  
Daya Bay ◽  
Mass Model ◽  
Big Bang Nucleosynthesis ◽  
Great Discovery ◽  
Neutrino Mass Models ◽  
The Universe ◽  
Inflationary Models

We construct the neutrino mass models with non-vanishing θ13 and estimate the baryon asymmetry of the universe and subsequently derive the constraints on the inflaton mass and the reheating temperature after inflation. The great discovery of this decade, the detection of Higgs boson of mass 126 GeV and nonzero θ13, makes leptogenesis all the more exciting. Besides, the neutrino mass model is compatible with inflaton mass 1010–1013 GeV corresponding to reheating temperature TR ∼ 105–107 GeV to overcome the gravitino constraint in supersymmetry and big bang nucleosynthesis. When Daya Bay data θ13 ≈ 9° is included in the model, τ predominates over e and μ contributions, which are indeed a good sign. It is shown that neutrino mass models for a successful leptogenesis can be accommodated for a variety of inflationary models with a rather wide ranging inflationary scale.

scholarly journals Doubly charged scalar decays in a type II seesaw scenario with two Higgs triplets

2014 ◽  
Vol 2014 (2) ◽  
Author(s):  
Avinanda Chaudhuri ◽  
Walter Grimus ◽  
Biswarup Mukhopadhyaya
Keyword(s):  
Type Ii ◽  
Charged Scalar ◽  
Doubly Charged
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