Duality in LeftRight Symmetric Seesaw Mechanism
Abstract
We consider type I+II seesaw mechanism, where the exchanges of both righthanded neutrinos and isotriplet Higgs bosons contribute to the neutrino mass. Working in the leftright symmetric framework and assuming the mass matrix of light neutrinos m{sub {nu}} and the Diractype Yukawa couplings to be known, we find the triplet Yukawa coupling matrix f, which carries the information about the masses and mixing of the righthanded neutrinos. We show that in this case there exists a duality: for any solution f, there is a dual solution fcircumflex=m{sub {nu}}/v{sub L}f, where v{sub L} is the vacuum expectation value of the triplet Higgs boson. Thus, unlike in pure type I (II) seesaw, there is no unique allowed structure for the matrix f. For n lepton generations the number of solutions is 2{sup n}. We develop an exact analytic method of solving the seesaw nonlinear matrix equation for f.
 Authors:
 Physik Department T30, Technische Universitaet Muenchen, JamesFranck Strasse, D85748 Garching (Germany)
 (Russian Federation)
 Department of Physics, University of California, Riverside, California 92521 (United States)
 Publication Date:
 OSTI Identifier:
 20778606
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review Letters; Journal Volume: 96; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevLett.96.061802; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; DUALITY; EQUATIONS; EXPECTATION VALUE; HIGGS BOSONS; MASS; MATHEMATICAL SOLUTIONS; NEUTRINO OSCILLATION; NEUTRINOS; NONLINEAR PROBLEMS; TRIPLETS; YUKAWA POTENTIAL
Citation Formats
Akhmedov, E.Kh., Kurchatov Institute, Moscow, and Frigerio, M. Duality in LeftRight Symmetric Seesaw Mechanism. United States: N. p., 2006.
Web. doi:10.1103/PHYSREVLETT.96.0.
Akhmedov, E.Kh., Kurchatov Institute, Moscow, & Frigerio, M. Duality in LeftRight Symmetric Seesaw Mechanism. United States. doi:10.1103/PHYSREVLETT.96.0.
Akhmedov, E.Kh., Kurchatov Institute, Moscow, and Frigerio, M. Fri .
"Duality in LeftRight Symmetric Seesaw Mechanism". United States.
doi:10.1103/PHYSREVLETT.96.0.
@article{osti_20778606,
title = {Duality in LeftRight Symmetric Seesaw Mechanism},
author = {Akhmedov, E.Kh. and Kurchatov Institute, Moscow and Frigerio, M.},
abstractNote = {We consider type I+II seesaw mechanism, where the exchanges of both righthanded neutrinos and isotriplet Higgs bosons contribute to the neutrino mass. Working in the leftright symmetric framework and assuming the mass matrix of light neutrinos m{sub {nu}} and the Diractype Yukawa couplings to be known, we find the triplet Yukawa coupling matrix f, which carries the information about the masses and mixing of the righthanded neutrinos. We show that in this case there exists a duality: for any solution f, there is a dual solution fcircumflex=m{sub {nu}}/v{sub L}f, where v{sub L} is the vacuum expectation value of the triplet Higgs boson. Thus, unlike in pure type I (II) seesaw, there is no unique allowed structure for the matrix f. For n lepton generations the number of solutions is 2{sup n}. We develop an exact analytic method of solving the seesaw nonlinear matrix equation for f.},
doi = {10.1103/PHYSREVLETT.96.0},
journal = {Physical Review Letters},
number = 6,
volume = 96,
place = {United States},
year = {Fri Feb 17 00:00:00 EST 2006},
month = {Fri Feb 17 00:00:00 EST 2006}
}

A leftright symmetric model is discussed with new mirror fermions and a Higgs sector with two doublets and neutral scalar singlets. The seesaw mechanism is generalized, including not only neutrino masses but also charged fermion masses. The spectrum of heavy neutrinos presents a second seesaw mass matrix and has neutrinos masses naturally in the TeV region. The model has very clear signatures for the new neutral vector gauge bosons. Two classes of models are discussed. New mirror neutrinos can be very light and a new Z{sup '} can be discriminated from other models by a very high invisible branching fraction.more »

Radiative seesaw in leftright symmetric model
There are some radiative origins for the neutrino masses in the conventional leftright symmetric models with the usual bidoublet and triplet Higgs scalars. These radiative contributions could dominate over the treelevel seesaw and could explain the observed neutrino masses. 
Triplet leptogenesis in leftright symmetric seesaw models
We discuss scalar triplet leptogenesis in a specific leftright symmetric seesaw model. We show that the Majorana phases that are present in the model can be effectively used to saturate the existing upper limit on the CPasymmetry of the triplets. We solve the relevant Boltzmann equations and analyze the viability of triplet leptogenesis. It is known for this kind of scenario that the efficiency of leptogenesis is maximal if there exists a hierarchy between the branching ratios of the triplet decays into leptons and Higgs particles. We show that triplet leptogenesis typically favors branching ratios with not too strong hierarchies,more » 
FCNCs in leftright symmetric theories and constraints on the righthanded scale
We revise the limits on the FCNC Higgs bosons in manifestly leftright symmetric theories. It is shown that the combination of KobayashiMaskawa CP violation with treelevel {Delta}S=2 Higgs boson exchange gives a very large contribution to the CPviolating {epsilon} parameter. It leads to a new strong constraint on the FCNC Higgs boson mass, M{gt}50{endash}100 TeV, enhanced by a factor of the order of {radical}(m{sub t}/m{sub c}). Being addressed to the supersymmetric leftright models, the FCNC problem requires that both the righthanded scale and supersymmetric mass parameters be heavier than 50 TeV for tan{beta}{approximately}1. The most relaxed case corresponds to tan{beta}{approximately}20{endash}30more »