scholarly journals Natural Higgs inflation, gauge coupling unification, and neutrino masses

2020 ◽  
Vol 35 (21) ◽  
pp. 2050117
Author(s):  
Heng-Yu Chen ◽  
Ilia Gogoladze ◽  
Shan Hu ◽  
Tianjun Li ◽  
Lina Wu

We present a class of nonsupersymmetric models in which the so-called critical Higgs inflation [Formula: see text] can be naturally realized without using specific values for Higgs and top quark masses. In these scenarios, the Standard Model (SM) vacuum stability problem, gauge coupling unification, neutrino mass generation and Higgs inflation mechanism are linked to each other. We adopt in our models Type I seesaw mechanism for neutrino masses. An appropriate choice of the Type I seesaw scale allows us to have an arbitrarily small but positive value of SM Higgs quartic coupling around the inflation scale. We present a few benchmark points where we show that the scalar spectral indices are around 0.9626 and 0.9685 for the number of [Formula: see text]-folding [Formula: see text] and [Formula: see text], respectively. The tensor-to-scalar ratios are of the order of [Formula: see text]. The running of the scalar spectral index is negative and is of the order of [Formula: see text].

2014 ◽  
Vol 29 (40) ◽  
pp. 1450212 ◽  
Author(s):  
Ernesto A. Matute

An extension of the Standard Model (SM) is studied in which two right-handed (RH) neutrinos per generation are incorporated, but considering the hypothesis of the symmetry of lepton and quark contents in order to deprive the number of RH neutrinos of freedom, generate Dirac neutrinos and accommodate naturally tiny values for their masses. The high scale type-I seesaw regime is applied to the first, ordinary RH neutrino, whereas a low scale pseudo-Dirac scenario is used for the second, adulterant RH neutrino, implying that the first RH neutrino decouples at the high scale, while the second RH neutrino survives down to the low scale to pair off in a Dirac-like form with the corresponding left-handed (LH) neutrino. The small mass and couplings of this extra RH neutrino are explained by means of the statement of the symmetry of fermionic content, only regarded as a guideline to the natural choice of parameters since it is not a proper symmetry in the Lagrangian.


2002 ◽  
Vol 17 (13) ◽  
pp. 771-778 ◽  
Author(s):  
SALAH NASRI ◽  
SHERIF MOUSSA

We propose a model for neutrino mass generation in which no physics beyond a TeV is required. We extend the standard model by adding two charged singlet fields with lepton number two. Dirac neutrino masses mνD ≤ MeV are generated at the one-loop level. Small left-handed Majorana neutrino masses can be generated via the seesaw mechanism with right-handed neutrino masses MR of order TeV scale.


2019 ◽  
Vol 34 (08) ◽  
pp. 1950047
Author(s):  
Marco Chianese ◽  
Damiano F. G. Fiorillo ◽  
Gennaro Miele ◽  
Stefano Morisi

One of the main purposes of SHiP experiment is to shed light on neutrino mass generation mechanisms like the so-called seesaw. We consider a minimal type-I seesaw neutrino mass mechanism model with two heavy neutral leptons (right-handed or sterile neutrinos) with arbitrary masses. Extremely high active-sterile mixing angle requires a correlation between the phases of the Dirac neutrino couplings. Actual experimental limits on the half-life of neutrinoless double beta decay [Formula: see text]-rate on the active-sterile mixing angle are not significative in constraining the masses or the mixing measurable by SHiP.


2017 ◽  
Vol 32 (16) ◽  
pp. 1750093 ◽  
Author(s):  
J. C. Montero ◽  
V. Pleitez ◽  
B. L. Sánchez-Vega ◽  
M. C. Rodriguez

We build a supersymmetric version with [Formula: see text] gauge symmetry, where [Formula: see text] is a new charge and [Formula: see text] and [Formula: see text] are the usual baryonic and leptonic numbers. The model has three right-handed neutrinos with identical [Formula: see text] charges, and can accommodate all fermion masses at the tree level. In particular, the type I seesaw mechanism is implemented for the generation of the active neutrino masses. We obtain the mass spectra of all sectors and for the scalar one we also give the flat directions allowed by the model.


2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Amit Chakraborty ◽  
Stefano Moretti ◽  
Claire H. Shepherd-Themistocleous ◽  
Harri Waltari

Abstract We study displaced signatures of sneutrino pairs potentially emerging at the Large Hadron Collider (LHC) in a Next-to-Minimal Supersymmetric Standard Model supplemented with right-handed neutrinos triggering a Type-I seesaw mechanism. We show how such signatures can be established through a heavy Higgs portal, the sneutrinos then decaying to charged leptons and charginos giving rise to further leptons or hadrons. We finally illustrate how the Yukawa parameters of neutrinos can be extracted by measuring the lifetime of the sneutrino from the displaced vertices, thereby characterising the dynamics of the underlying mechanism of neutrino mass generation. We show our numerical results for the case of both the current and High-Luminosity LHC.


Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1418
Author(s):  
Simonas Draukšas ◽  
Vytautas Dūdėnas ◽  
Thomas Gajdosik ◽  
Andrius Juodagalvis ◽  
Paulius Juodsnukis ◽  
...  

The Grimus–Neufeld model can explain the smallness of measured neutrino masses by extending the Standard Model with a single heavy neutrino and a second Higgs doublet, using the seesaw mechanism and radiative mass generation. The Grimus–Lavoura approximation allows us to calculate the light neutrino masses analytically. By inverting these analytic expressions, we determine the neutrino Yukawa couplings from the measured neutrino mass differences and the neutrino mixing matrix. Short-cutting the full renormalization of the model, we implement the Grimus–Neufeld model in the spectrum calculator FlexibleSUSY and check the consistency of the implementation. These checks hint that FlexibleSUSY is able to do the job of numerical renormalization in a restricted parameter space. As a summary, we also comment on further steps of the implementation and the use of FlexibleSUSY for the model.


2016 ◽  
Vol 31 (25) ◽  
pp. 1650142 ◽  
Author(s):  
Guillermo Palacio

We study the neutrino mass generation in the [Formula: see text] electroweak extension of the Standard Model by considering nonrenormalizable dimension 5 effective operators. It is shown that there exist two topologies for the realizations of such an operator at the tree-level and for one of the three-family models the neutrino phenomenology is explored after extending its particle content with an [Formula: see text] fermion singlet and a scalar decuplet. Constraints in the available parameters space of the model are partially discussed.


2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Shilpa Jangid ◽  
Priyotosh Bandyopadhyay ◽  
P.S. Bhupal Dev ◽  
Arjun Kumar

Abstract We analyze the vacuum stability in the inert Higgs doublet extension of the Standard Model (SM), augmented by right-handed neutrinos (RHNs) to explain neutrino masses at tree level by the seesaw mechanism. We make a comparative study of the high- and low-scale seesaw scenarios and the effect of the Dirac neutrino Yukawa couplings on the stability of the Higgs potential. Bounds on the scalar quartic couplings and Dirac Yukawa couplings are obtained from vacuum stability and perturbativity considerations. These bounds are found to be relevant only for low-scale seesaw scenarios with relatively large Yukawa couplings. The regions corresponding to stability, metastability and instability of the electroweak vacuum are identified. These theoretical constraints give a very predictive parameter space for the couplings and masses of the new scalars and RHNs which can be tested at the LHC and future colliders. The lightest non-SM neutral CP-even/odd scalar can be a good dark matter candidate and the corresponding collider signatures are also predicted for the model.


Author(s):  
Sudhanwa Patra ◽  
Utkarsh Patel ◽  
Purushottam Sahu

The presence of small neutrino masses and flavour mixings can be accounted for naturally in various models about extensions of the standard model, particularly in the seesaw mechanism models. In this work, we present a minimally extended seesaw framework with two right-handed neutrinos, where the active neutrino masses are derived in the radiative regime. Using the framework it can be shown that within certain mass limits, the light neutrino mass term can approach a form that is similar to its form under type-I seesaw mechanism. Apart from this, we show that the decay width of right-handed neutrinos (produced through the decay of [Formula: see text] boson in a particle collider) is short enough to cause a sufficiently long lifetime for the particles, thus ensuring an observable displacement in the LHC between the production and decay vertices. We comment on the fact that these displaced vertex signatures thus can serve as a means to verify the existence of these right-handed neutrinos in future experiments. Lastly, we line up the possibility of our future work where the vertex signatures of particles greater than the mass of [Formula: see text] boson can be worked upon.


2021 ◽  
pp. 2150184
Author(s):  
V. V. Vien ◽  
H. N. Long ◽  
D. P. Khoi

In this paper, we study a non-renormalizable [Formula: see text] extension of the Standard Model with [Formula: see text] and [Formula: see text] symmetries accommodating the most recent neutrino data within the type-I seesaw mechanism. The two squared mass differences and three mixing angles can get the best-fit values while the leptonic Dirac CP phase is in [Formula: see text] range of the best-fit values for both normal and inverted orderings. The sum of active neutrino mass and the effective neutrino masses are, respectively, predicted to be [Formula: see text], [Formula: see text] and [Formula: see text] for normal ordering while [Formula: see text], [Formula: see text] and [Formula: see text] for inverted ordering, which are well consistent with the current experimental constraints.


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