scholarly journals Electroweak symmetry breaking in the inverse seesaw mechanism

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Sanjoy Mandal ◽  
Rahul Srivastava ◽  
José W. F. Valle
Keyword(s):  
Planck Scale ◽  
Lepton Number ◽  
Electroweak Symmetry Breaking ◽  
Electroweak Symmetry ◽  
Seesaw Mechanism ◽  
Yukawa Couplings ◽  
Lepton Number Violation ◽  
Higgs Vacuum ◽  
The Standard Model ◽  
The Stability

Abstract We investigate the stability of Higgs potential in inverse seesaw models. We derive the full two-loop RGEs of the relevant parameters, such as the quartic Higgs self-coupling, taking thresholds into account. We find that for relatively large Yukawa couplings the Higgs quartic self-coupling goes negative well below the Standard Model instability scale ∼ 1010 GeV. We show, however, that the “dynamical” inverse seesaw with spontaneous lepton number violation can lead to a completely consistent and stable Higgs vacuum up to the Planck scale.

scholarly journals Dynamical inverse seesaw mechanism as a simple benchmark for electroweak breaking and Higgs boson studies

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Sanjoy Mandal ◽  
Jorge C. Romão ◽  
Rahul Srivastava ◽  
José W. F. Valle
Keyword(s):  
Higgs Boson ◽  
Goldstone Boson ◽  
Lepton Number ◽  
Higgs Bosons ◽  
Vacuum Stability ◽  
Seesaw Mechanism ◽  
Decay Channels ◽  
Lepton Number Violation ◽  
The Standard Model ◽  
Scale Breaking

Abstract The Standard Model (SM) vacuum is unstable for the measured values of the top Yukawa coupling and Higgs mass. Here we study the issue of vacuum stability when neutrino masses are generated through spontaneous low-scale lepton number violation. In the simplest dynamical inverse seesaw, the SM Higgs has two siblings: a massive CP-even scalar plus a massless Nambu-Goldstone boson, called majoron. For TeV scale breaking of lepton number, Higgs bosons can have a sizeable decay into the invisible majorons. We examine the interplay and complementarity of vacuum stability and perturbativity restrictions, with collider constraints on visible and invisible Higgs boson decay channels. This simple framework may help guiding further studies, for example, at the proposed FCC facility.

scholarly journals NEUTRINO MASS MATRICES IN MODELS WITH HORIZONTAL SYMMETRIES

2001 ◽  
Vol 16 (36) ◽  
pp. 2345-2352 ◽  
Author(s):  
ASIM K. RAY ◽  
UTPAL SARKAR
Keyword(s):  
Neutrino Mass ◽  
Majorana Neutrino ◽  
Mass Scale ◽  
Lepton Number ◽  
Yukawa Couplings ◽  
Lepton Number Violation ◽  
Mass Matrices ◽  
The Standard Model ◽  
Low Mass ◽  
Majorana Neutrino Mass

We have studied the most general neutrino mass matrices in models with SU(2) and SU(3) horizontal symmetries. Without going into the details of the models it is possible to write down the effective operators, which predict the structure of the Majorana neutrino mass matrices. Unlike other extensions of the standard model, the structure is now independent of the effective Yukawa couplings and depends entirely on the Higgs which gives mass to the other fermions. In the case of SU(3) symmetries the lowest dimensional operators are forbidden requiring a low mass scale for lepton number violation.

scholarly journals Vacuum stability in inert higgs doublet model with right-handed neutrinos

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Shilpa Jangid ◽  
Priyotosh Bandyopadhyay ◽  
P.S. Bhupal Dev ◽  
Arjun Kumar
Keyword(s):  
Higgs Doublet ◽  
Tree Level ◽  
Dark Matter Candidate ◽  
Neutrino Masses ◽  
Vacuum Stability ◽  
Seesaw Mechanism ◽  
Yukawa Couplings ◽  
The Standard Model ◽  
Doublet Model ◽  
The Stability

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.

scholarly journals Dark matter spectra from the electroweak to the Planck scale

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Christian W. Bauer ◽  
Nicholas L. Rodd ◽  
Bryan R. Webber
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Symmetry Breaking ◽  
Planck Scale ◽  
Electroweak Symmetry Breaking ◽  
Indirect Detection ◽  
Electroweak Symmetry ◽  
Stable States ◽  
Decay Spectrum ◽  
Crucial Ingredient

Abstract We compute the decay spectrum for dark matter (DM) with masses above the scale of electroweak symmetry breaking, all the way to the Planck scale. For an arbitrary hard process involving a decay to the unbroken standard model, we determine the prompt distribution of stable states including photons, neutrinos, positrons, and antiprotons. These spectra are a crucial ingredient in the search for DM via indirect detection at the highest energies as being probed in current and upcoming experiments including IceCube, HAWC, CTA, and LHAASO. Our approach improves considerably on existing methods, for instance, we include all relevant electroweak interactions.

scholarly journals WHAT IS A MATTER PARTICLE?

2006 ◽  
Vol 15 (01) ◽  
pp. 259-272
Author(s):  
TSAN UNG CHAN
Keyword(s):  
Standard Model ◽  
Weak Interaction ◽  
Strong Interaction ◽  
Neutral Particle ◽  
Z Bosons ◽  
Baryon Number ◽  
Lepton Number ◽  
Neutral Particles ◽  
The Standard Model ◽  
The Stability

Positive baryon numbers (A>0) and positive lepton numbers (L>0) characterize matter particles while negative baryon numbers and negative lepton numbers characterize antimatter particles. Matter particles and antimatter particles belong to two distinct classes of particles. Matter neutral particles are particles characterized by both zero baryon number and zero lepton number. This third class of particles includes mesons formed by a quark and an antiquark pair (a pair of matter particle and antimatter particle) and bosons which are messengers of known interactions (photons for electromagnetism, W and Z bosons for the weak interaction, gluons for the strong interaction). The antiparticle of a matter particle belongs to the class of antimatter particles, the antiparticle of an antimatter particle belongs to the class of matter particles. The antiparticle of a matter neutral particle belongs to the same class of matter neutral particles. A truly neutral particle is a particle identical with its antiparticle; it belongs necessarily to the class of matter neutral particles. All known interactions of the Standard Model conserve baryon number and lepton number; matter cannot be created or destroyed via a reaction governed by these interactions. Conservation of baryon and lepton number parallels conservation of atoms in chemistry; the number of atoms of a particular species in the reactants must equal the number of those atoms in the products. These laws of conservation valid for interaction involving matter particles are indeed valid for any particles (matter particles characterized by positive numbers, antimatter particles characterized by negative numbers, and matter neutral particles characterized by zero). Interactions within the framework of the Standard Model which conserve both matter and charge at the microscopic level cannot explain the observed asymmetry of our Universe. The strong interaction was introduced to explain the stability of nuclei: there must exist a powerful force to compensate the electromagnetic force which tends to cause protons to fly apart. The weak interaction with laws of conservation different from electromagnetism and the strong interaction was postulated to explain beta decay. Our observed material and neutral universe would signify the existence of another interaction that did conserve charge but did not conserve matter.

scholarly journals Constraining the gauge and scalar sectors of the doublet left-right symmetric model

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Véronique Bernard ◽  
Sébastien Descotes-Genon ◽  
Luiz Vale Silva
Keyword(s):  
Symmetry Breaking ◽  
Electroweak Symmetry Breaking ◽  
Symmetric Model ◽  
Electroweak Symmetry ◽  
Gauge Bosons ◽  
Spontaneous Breakdown ◽  
The Standard Model ◽  
Low Energies ◽  
Precision Observables ◽  
Electroweak Precision

Abstract We consider a left-right symmetric extension of the Standard Model where the spontaneous breakdown of the left-right symmetry is triggered by doublets. The electroweak ρ parameter is protected from large corrections in this Doublet Left-Right Model (DLRM), contrary to the triplet case. This allows in principle for more diverse patterns of symmetry breaking. We consider several constraints on the gauge and scalar sectors of DLRM: the unitarity of scattering processes involving gauge bosons with longitudinal polarisations, the radiative corrections to the muon ∆r parameter and the electroweak precision observables measured at the Z pole and at low energies. Combining these constraints within the frequentist CKMfitter approach, we see that the fit pushes the scale of left-right symmetry breaking up to a few TeV, while favouring an electroweak symmetry breaking triggered not only by the SU(2)L×SU(2)R bi-doublet, which is the case most commonly considered in the literature, but also by the SU(2)L doublet.

RADIATIVE EFFECTS AND ELECTROWEAK SYMMETRY BREAKING IN A SUPERSYMMETRIC PREON MODEL

1999 ◽  
Vol 14 (09) ◽  
pp. 1389-1427
Author(s):  
JONGBAE KIM
Keyword(s):  
Symmetry Breaking ◽  
Dynamical Symmetry ◽  
Electroweak Symmetry Breaking ◽  
Effective Theory ◽  
Supersymmetric Particle ◽  
Electroweak Symmetry ◽  
Radiative Effects ◽  
Yukawa Couplings ◽  
Lepton Universality

We construct the low energy effective theory of composite quarks, leptons, and Higgs bosons for a supersymmetric preon model and study the effects of renormalization-group based radiative corrections. The study on the evolution of scalar masses for avoiding color and charge breakings leads us to conclude that Yukawa couplings are bounded from above. The implementation of electroweak symmetry breaking requires that only the purely dynamical symmetry breaking should be needed for the model, but the combined scheme of dynamical and radiative symmetry breaking as well as the purely radiative symmetry breaking scheme be disfavored. Our analysis of [Formula: see text] including radiative effects shows that, should a discrepancy be found between the observed and the theoretical value of [Formula: see text] after experimental determination of supersymmetric particle masses, it would imply that the complete quark–lepton universality in the supersymmetric preon model does not hold either for the Yukawa couplings, or for the condensates, or for both.

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