scholarly journals Weak scale right-handed neutrino as pseudo-Goldstone fermion of spontaneously broken $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Anjan S. Joshipura ◽  
Ketan M. Patel
Keyword(s):  
Prototype Model ◽  
Neutrino Masses ◽  
Type I ◽  
Decay Vertex ◽  
Electroweak Scale ◽  
Seesaw Mechanism ◽  
Cosmological Constraints ◽  
Flavour Violation ◽  
Soft Supersymmetry Breaking ◽  
Parity Breaking

Abstract Possibility of a Right-Handed (RH) neutrino being a Goldstone fermion of a spontaneously broken global U(1) symmetry in a supersymmetric theory is considered. This fermion obtains mass from the supergravity effects leading to a RH neutrino at the electroweak scale with a mass similar to the gravitino mass. A prototype model realizing this scenario contains just three gauge singlet superfields needed for the type I seesaw mechanism. Masses of the other two neutrinos are determined by the U(1) breaking scale which too can be around the electroweak scale. Light neutrinos obtain their masses in this scenario through (a) mixing with the RH neutrinos (type I seesaw), (b) mixing with neutralinos (R-parity breaking), (c) indirectly through mixing of the RH neutrinos with neutralinos, and (d) radiative corrections. All these contributions are described by the same set of a small number of underlying parameters and provide a very constrained and predictive framework for the neutrino masses which is investigated in detail for various choices of U(1) symmetries. It is found that flavour independent U(1) symmetries cannot describe neutrino masses if the soft supersymmetry breaking terms are flavour universal and one needs to consider flavour dependent symmetries. Considering a particular example of Lμ− Lτ symmetry, it is shown that viable neutrino masses and mixing can be obtained without introducing any flavour violation in the soft sector. The leptonic couplings of Majoron are worked out in the model and shown to be consistent with various laboratory, astrophysical and cosmological constraints. The neutrino data allows sizeable couplings between the RH neutrinos and Higgsinos which can be used to probe the pseudo-Goldstone fermion at colliders through its displaced decay vertex.

scholarly journals Radiative Corrections toMhfrom Three Generations of Majorana Neutrinos and Sneutrinos

2015 ◽  
Vol 2015 ◽  
pp. 1-26 ◽  
Author(s):  
S. Heinemeyer ◽  
J. Hernandez-Garcia ◽  
M. J. Herrero ◽  
X. Marcano ◽  
A. M. Rodriguez-Sanchez
Keyword(s):  
Higgs Boson ◽  
Higgs Mass ◽  
Critical Discussion ◽  
Full Detail ◽  
Neutrino Masses ◽  
Type I ◽  
Radiative Corrections ◽  
Seesaw Mechanism ◽  
Three Generations ◽  
Majorana Neutrinos

We study the radiative corrections to the mass of the lightest Higgs boson of the MSSM from three generations of Majorana neutrinos and sneutrinos. The spectrum of the MSSM is augmented by three right handed neutrinos and their supersymmetric partners. A seesaw mechanism of type I is used to generate the physical neutrino masses and oscillations that we require to be in agreement with present neutrino data. We present a full one-loop computation of these Higgs mass corrections and analyze in full detail their numerical size in terms of both the MSSM and the new (s)neutrino parameters. A critical discussion on the different possible renormalization schemes and their implications, in particular concerning decoupling, is included.

scholarly journals Conformal GUT inflation, proton lifetime and non-thermal leptogenesis

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
K. Sravan Kumar ◽  
Paulo Vargas Moniz
Keyword(s):  
Conformal Symmetry ◽  
Lepton Number ◽  
Baryon Asymmetry ◽  
Neutrino Masses ◽  
Type I ◽  
Gauge Bosons ◽  
Seesaw Mechanism ◽  
Grand Unified Theories ◽  
Unified Theories ◽  
Proton Lifetime

AbstractIn this paper, we generalize Coleman–Weinberg (CW) inflation in grand unified theories (GUTs) such as $$\text {SU}(5)$$SU(5) and $$\text {SO}(10)$$SO(10) by means of considering two complex singlet fields with conformal invariance. In this framework, inflation emerges from a spontaneously broken conformal symmetry. The GUT symmetry implies a potential with a CW form, as a consequence of radiative corrections. The conformal symmetry flattens the above VEV branch of the CW potential to a Starobinsky plateau. As a result, we obtain $$n_{s}\sim 1-\frac{2}{N}$$ns∼1-2N and $$r\sim \frac{12}{N^2}$$r∼12N2 for $$N\sim $$N∼ 50–60 e-foldings. Furthermore, this framework allow us to estimate the proton lifetime as $$\tau _{p}\lesssim 10^{40}$$τp≲1040 years, whose decay is mediated by the superheavy gauge bosons. Moreover, we implement a type I seesaw mechanism by weakly coupling the complex singlet, which carries two units of lepton number, to the three generations of singlet right handed neutrinos (RHNs). The spontaneous symmetry breaking of global lepton number amounts to the generation of neutrino masses. We also consider non-thermal leptogenesis in which the inflaton dominantly decays into heavy RHNs that sources the observed baryon asymmetry. We constrain the couplings of the inflaton field to the RHNs, which gives the reheating temperature as $$10^{6}\text { GeV}\lesssim T_{R}<10^{9}$$106GeV≲TR<109 GeV.

scholarly journals Dirac neutrinos from Peccei–Quinn symmetry: A fresh look at the axion

2020 ◽  
Vol 35 (21) ◽  
pp. 2050176 ◽  
Author(s):  
Eduardo Peinado ◽  
Mario Reig ◽  
Rahul Srivastava ◽  
Jose W. F. Valle
Keyword(s):  
Neutrino Mass ◽  
Simple Solution ◽  
Neutrino Masses ◽  
Type I ◽  
Seesaw Mechanism

We show that a very simple solution to the strong CP problem naturally leads to Dirac neutrinos. Small effective neutrino masses emerge from a type-I Dirac seesaw mechanism. Neutrino mass limits probe the axion parameters in regions currently inaccessible to conventional searches.

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.

U(1)B−L extension based on Δ(27) symmetry for lepton masses and mixings

2020 ◽  
Vol 35 (22) ◽  
pp. 2050181
Author(s):  
V. V. Vien ◽  
D. P. Khoi
Keyword(s):  
Standard Model ◽  
Neutrino Oscillation ◽  
The Other ◽  
Physical Parameters ◽  
Neutrino Masses ◽  
Type I ◽  
Seesaw Mechanism ◽  
Global Fit ◽  
Experimental Values ◽  
Best Fit

We propose a [Formula: see text] Standard Model (SM) extension based on [Formula: see text] symmetry in which neutrino mass orderings and the tiny neutrino masses are produced by the type-I seesaw mechanism. The obtained physical parameters are well consistent with the global fit of neutrino oscillation.1 The model is predictive in the sense that it reproduces the experimental values of neutrino parameters. Two of the predicted parameters have little deviations from the best-fit values given in Ref. 1, however they are consistent with the other experimental results.[Formula: see text]

scholarly journals SO(10) × S4 grand unified theory of flavour and leptogenesis

2017 ◽  
Vol 2017 (12) ◽  
Author(s):  
Francisco J. de Anda ◽  
Stephen F. King ◽  
Elena Perdomo
Keyword(s):  
Neutrino Mass ◽  
Discrete Group ◽  
Double Beta Decay ◽  
Neutrino Masses ◽  
Type I ◽  
Unified Theory ◽  
Grand Unified Theory ◽  
Oscillation Phase ◽  
Seesaw Mechanism ◽  
Natural Range

Abstract We propose a Grand Unified Theory of Flavour, based on SO(10) together with a non-Abelian discrete group S 4, under which the unified three quark and lepton 16-plets are unified into a single triplet 3′. The model involves a further discrete group ℤ 4 R  × ℤ 4 3 which controls the Higgs and flavon symmetry breaking sectors. The CSD2 flavon vacuum alignment is discussed, along with the GUT breaking potential and the doublet-triplet splitting, and proton decay is shown to be under control. The Yukawa matrices are derived in detail, from renormalisable diagrams, and neutrino masses emerge from the type I seesaw mechanism. A full numerical fit is performed with 15 input parameters generating 19 presently constrained observables, taking into account supersymmetry threshold corrections. The model predicts a normal neutrino mass ordering with a CP oscillation phase of 260°, an atmospheric angle in the first octant and neutrinoless double beta decay with m ββ = 11 meV. We discuss N 2 leptogenesis, which fixes the second right-handed neutrino mass to be M 2 ≃ 2 × 1011 GeV, in the natural range predicted by the model.

scholarly journals Supersymmetric U(1)Y′⊗ U(1)B−L extension of the Standard Model

2017 ◽  
Vol 32 (16) ◽  
pp. 1750093 ◽  
Author(s):  
J. C. Montero ◽  
V. Pleitez ◽  
B. L. Sánchez-Vega ◽  
M. C. Rodriguez
Keyword(s):  
Gauge Symmetry ◽  
Mass Spectra ◽  
Tree Level ◽  
Neutrino Masses ◽  
Type I ◽  
Seesaw Mechanism ◽  
Active Neutrino ◽  
Supersymmetric Version ◽  
Fermion Masses ◽  
The Standard Model

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.

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
Keyword(s):  
Top Quark ◽  
Gauge Coupling ◽  
Neutrino Masses ◽  
Type I ◽  
Mass Generation ◽  
Vacuum Stability ◽  
Seesaw Mechanism ◽  
Quark Masses ◽  
The Standard Model ◽  
Neutrino Mass Generation

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].

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