Explicit SO(10) supersymmetric grand unified model for the higgs and yukawa sectors

A complete set of fermion and Higgs superfields is introduced with well-defined SO(10) properties and U(1)xZ2xZ2 family charges from which the Higgs and Yukawa superpotentials are constructed. The structures derived for the four Dirac fermion and right-handed Majorana neutrino mass matrices coincide with those previously obtained from an effective operator approach. Ten mass matrix input parameters accurately yield the twenty masses and mixings of the quarks and leptons with the bimaximal atmospheric and solar neutrino vacuum solutions favored in this simplest version.     

Probing the seesaw mechanism with neutrino data and leptogenesis

We use the current low-energy neutrino data to understand the structure of the neutrino mass matrix. Considering this information and assuming hierarchical neutrino Yukawa couplings, we use the seesaw formula to study the properties of the heavy right-handed neutrinos N_i. We find that successful baryogenesis via leptogenesis requires mass degeneracy and maximal mixing of N₁ and N₂.     

Dirac neutrino masses from generalized supersymmetry breaking

We demonstrate that Dirac neutrino masses in the experimentally preferred range are generated within supersymmetric gauge extensions of the standard model with a generalized supersymmetry breaking sector. If the superpotential neutrino Yukawa terms are forbidden by the gauge symmetry [such as a U(1)'], sub-eV scale effective Dirac mass terms can arise at tree level from hard supersymmetry breaking Yukawa couplings, or at one loop due to nonanalytic soft supersymmetry breaking trilinear scalar couplings. The radiative neutrino magnetic and electric dipole moments vanish at one-loop order.     

Dirac vs. Majorana neutrino masses from a TeV interval

We investigate the nature (Dirac vs. Majorana) and size of left-handed neutrino masses in a supersymmetric five-dimensional model compactified in the interval [0,πR], where quarks and leptons are localized on the boundaries while the gauge and Higgs sectors propagate in the bulk of the fifth dimension. Supersymmetry is broken by Scherk–Schwarz boundary conditions and electroweak breaking proceeds through radiative corrections. Right-handed neutrinos propagate in the bulk and have a general five-dimensional mass M, which localizes the zero modes towards one of the boundaries, and arbitrary boundary terms. We have found that for generic boundary terms left-handed neutrinos have Majorana masses. However for specific boundary configurations left-handed neutrinos are Dirac fermions as the theory possesses a conserved global U(1) symmetry which prevents violation of lepton number. The size of neutrino masses depends on the localization of the zero-modes of right-handed neutrinos and/or the size of the five-dimensional neutrino Yukawa couplings. Left-handed neutrinos in the sub-eV range require either MR10 or Yukawa couplings 10⁻³R, which make the five-dimensional theory perturbative up to its natural cutoff.     

NEUTRINO MAGNETIC MOMENT IN SUPERSTRING INSPIRED MODELS

In superstring E₆ models right-handed leptonic currents can arise from the mixing between the ordinary leptons and tha exotic leptons. Contributions to the neutrino magnetic moment due to this new interaction are examined. Although the result appears to be directly proportional to the heavy exotic charged lepton mass, it is shown, however, that the mixing is proportional to the ratio of the neutrino mass and the exotic lepton mass. The combination of these two factors yields a result which is of the order of that given by the SU(2)_LxU(1)_Y model.     

Neutrino-neutralino mixing and one-loop corrections in the R-parity violating supersymmetric model

We consider the supersymmetric extension of the Standard Model with neutrino Yukawa interactions and R-parity violation. We calculate one-loop corrections to physical neutrino mass in case of neutrinoneutralino mixing and discuss the influence of this mass shift on parameter constraints.     

Some constraints on the Yukawa parameters in the neutrino modification of the Standard Model (ν<Emphasis Type="Italic">MSM</Emphasis>) and CP-violation

The equations connecting elements of the Yukawa matrix to elements of the active neutrino mass matrix in the νMSM theory (an extension of the Standard Model by a singlet of three right-handed neutrinos) was analyzed, and explicit relations for the ratio of the Yukawa matrix elements and elements of the active neutrino mass matrix were obtained. This relation can be used for getting more accurate constraints on the model parameters. Particularly, with the help of the obtained results we investigated CP-violating phase in the νMSM theory. We demonstrate that even in the case when elements of the active neutrino mass matrix are real the baryon asymmetry can be generated also.     

Neutrino masses and lepton-flavor-violating τ decays in the supersymmetric left-right model

In the supersymmetric left-right model,the light neutrino masses are given by the Type-II seesaw mechanism.A duality property of this mechanism indicates that there exist eight possible Higgs triplet Yukawa couplings which result in the same neutrino ma6s matrix.In this paper,we work out the one-loop renormalization group equations for the effective neutrino mass matrix in the supersymmetric left-right model.The stability of the Type-II seesaw scenario is briefly discussed.We also study the lepton-flavor-violating processes (τ→μγ and τ→eγ)by using the reconstructed Higgs triplet Yukawa couplings.     

Neutrino masses and lepton-flavor-violating τ decays in the supersymmetric left-right model

In the supersymmetric left-right model, the light neutrino masses are given by the Type-Ⅱ seesaw mechanism. A duality property of this mechanism indicates that there exist eight possible Higgs triplet Yukawa couplings which result in the same neutrino mass matrix. In this paper, we work out the one-loop renormalization group equations for the effective neutrino mass matrix in the supersymmetric left-right model. The stability of the Type-Ⅱ seesaw scenario is briefly discussed. We also study the lepton-flavor-violating processes (τ→ μγ and τ→eγ) by using the reconstructed Higgs triplet Yukawa couplings.     

The interplay between “low” and “high” energy CP-violation in leptogenesis

We analyse, within the “flavoured” leptogenesis scenario of baryon asymmetry generation, the interplay of “low energy” CP-violation, originating from the PMNS neutrino mixing matrix U, and “high energy” CP-violation, which can be present in the matrix of neutrino Yukawa couplings, λ, and can manifest itself only in “high” energy scale processes. The type I see-saw model with three heavy right-handed Majorana neutrinos having a hierarchical spectrum is considered. The “orthogonal” parameterisation of the matrix of neutrino Yukawa couplings, which involves a complex orthogonal matrix R, is employed. In this approach the matrix R is the source of “high energy” CP-violation. Results for normal hierarchical (NH) and inverted hierarchical (IH) light neutrino mass spectrum are derived in the case of decoupling of the heaviest right-handed Majorana neutrino. It is shown that taking into account the contribution to Y _B due to the CP-violating phases in the neutrino mixing matrix U can change drastically the predictions for Y _B , obtained assuming that only “high energy” CP-violation from the R-matrix is operative in leptogenesis. In the case of the IH spectrum, in particular, there exist significant regions in the corresponding parameter space where the purely “high energy” contribution in Y _B plays a subdominant role in the production of baryon asymmetry compatible with the observations. Also at Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria.     

Algebraic construction of static axially symmetric self-dual gauge fields for an arbitrary group

It is suggested that the Higgs and the Yukawa couplings of the standard model possess two global U(1)-symmetries: independent chiral rotations of quarks and leptons. The model requires the existence of two axions, one of which (massive) does not interact with leptons, whereas the second one interacts both with leptons and quarks.     

Electron-muon mass ratio and the masses of their neutrinos

In this note, we arrange equal mass for all the four leptons,e,, and their neutrinos through their coupling to a Higg's quartet. In addition, the electron and muon are coupled to the left handed and right handed Higgs doublets. This is a pseudo scalar coupling. This enables these charged leptons to attain different masses. Their masses are arranged to be proportional to their neutrino mass. The mass of the electron or muon neutrino turns out to be 6.3 eV.     

New parametrisation of tri-bimaximal mixings

Recent neutrino oscillation data indicates tri-bimaximal mixings. In this communication we propose degenerate, inverted hierarchical and normal hierarchical structures of neutrino mass matrices in terms of two input parameters. These mass matrices not only predict tri-bimaximal mixings but also neutrino oscillation mass parameters comparable with experimental data. We consider contribution of Type-II seesaw formula and observe possible deviations from tri-bimaximal mixings.     

Mass and CKM matrices of quarks and leptons, the leptonic CP-phase in neutrino oscillations

A general approach for construction of quark and lepton mass matrices is formulated. The hierarchy of quarks and charged leptons (“electrons”) is large, it leads using the experimental values of mixing angles to the hierarchical mass matrix slightly deviating from the ones suggested earlier by Stech and including naturally the CP-phase.

The same method based on the rotation of generation numbers in the diagonal mass matrix is used in the electron–neutrino sector of theory, where neutrino mass matrix is determined by the Majorano see-saw approach. The hierarchy of neutrino masses, much smaller than for quarks, was used including all existing (even preliminary) experimental data on neutrino mixing.

The leptonic mass matrix found in this way includes the unknown value of the leptonic CP-phase. It leads to large ν_μν_τ oscillations and suppresses the ν_eν_τ and also ν_eν_μ oscillations. The explicit expressions for the probabilities of neutrino oscillation were obtained in order to specify the role of leptonic CP-phase. The value of time reversal effect (proportional to sin δ′) was found to be small 1%. However, a dependence of the values of ν_eν_μ,ν_eν_τ transition probabilities, averaged over oscillations, on the leptonic CP-phase has found to be not small – of order of ten percent.     

Some new symmetric relations and prediction of left-and right-handed neutrino masses using Koide's relation

The masses of the three generations of charged leptons are known to completely satisfy Koide's mass relation,but the question remains of whether such a relation exists for neutrinos.In this paper,by considering the seesaw mechanism as the mechanism generating tiny neutrino masses,we show how neutrinos satisfy Koide's mass relation,on the basis of which we systematically give exact values of both left-and right-handed neutrino masses.     

Supersymmetry for Fermion Masses

It is proposed that supersymmetry （SUSY） may be used to understand fermion mass hierarchies. A family symmetry ZSL is introduced, which is the cyclic symmetry among the three generation SU（2） doublets. SUSY breaks at a high energy scale - 10^11 GeV. The electroweak energy scale- 100 GeV is unnaturally small No additional global symmetry, like the R-parlty, is imposed. The Yukawa couplings and R-parity violating couplings all take their natural values, which are О（10^0 -10^-2）. Under the family symmetry, only the third generation charged ferrnions get their masses. This family symmetry is broken in the soft SUSY breaking terms, which result in a hierarchical pattern of the fermion masses. It turns out that for the charged leptons, the r mass is from the Higgs vacuum expectation value （VEV） and the sneutrino VEVs, the muon mass is due to the sneutrino VEVs, and the electron gains its mass due to both ZZL and SUSY hreaking. The large neutrino mixing are produced with neutralinos playing the partial role of right-handed neutrinos. │Ve3│, which is for Ve-Vr mixing, is expected to be about 0.1. For the quarks, the third generation masses are from the Higgs VEVs, the second generation masses are from quantum corrections, and the down quark mass due to the sneutrino VEVs. It explains me/ms, ms/me, md 〉 mu and so on. Other aspects of the model are discussed.     

Probing a supersymmetric model for neutrino masses at ultrahigh energy neutrino telescopes

A bilinear R-parity breaking SUSY model for neutrino mass and mixing predicts the lightest superparticle to decay mainly into a pair of tau leptons or b quarks along with a neutrino for relatively light SUSY spectra. This leads to a distinctive triple bang signature of SUSY events at ultrahigh energy neutrino telescopes like IceCube or Antares. While the expected signal size is only marginal at IceCube, it will be promising for a future multi-km³ size neutrino telescope.     

Lepton Electric Charge Swap at the 10 TeV Energy Scale

We investigate the nature of the dark matter by proposing a mechanism for the breaking of local rotational symmetry between ordinary third family leptons and proposed non-regular leptons at energy scales below 10 TeV. This symmetry breaking mechanism involves electric charge swap between ordinary families of leptons can and produces highly massive non-regular leptons of order 0 （1 TeV） mass unobservable at energy scales below 10 TeV （the scale of LEP Ⅰ, Ⅱ and neutrino oscillation experiments）. Electric charge swap between ordinary families of leptons produces heavy neutral non-regular leptons with order 0 （1 TeV） masses, which may form cold dark matter. The existence of these proposed leptons can be tested once the Large Hadron Collider （LHC） becomes operative at 10 TeV energy-scales. This proposition may have far reaching applications in astrophysics and cosmology.     

Hiding neutrinoless double beta decay in the minimal seesaw model with the TM1 or μ–τ reflection symmetry

In Asaka et al (2021 Phys. Rev. D 103, 015014), Asaka, Ishida and Tanaka put forward an interesting possibility that the neutrinoless double beta decay can be hidden in the minimal seesaw model with the two right-handed neutrinos having a hierarchical mass structure: the lighter one is lighter enough than the typical Fermi-momentum scale of nuclei while the heavier one is sufficiently heavy to decouple from the neutrinoless double beta decay. Then, in the basis where the mass matrices of the charged leptons and right-handed neutrinos are diagonal, for some particular texture of the Dirac neutrino mass matrix ${M}_{{\rm{D}}}^{}$, the neutrinoless double beta decay can be hidden. In this paper, on top of this specified model, we study the interesting scenario that ${M}_{{\rm{D}}}^{}$ further obeys the TM1 symmetry or μ–τ reflection symmetry which are well motivated by the experimental results for the neutrino mixing parameters.     

具有整体代对称性的左右对称模型中的中微子质量

本文基于具有整体U(1)代对称性的SU(2)_L×SU(2)_R×U(1)模型推导了轻子的味混合矩阵,对中微子的质量问题进行了研究.在本文的模型中,产生轻子Dirac质量的汤川耦合拉格朗日密度具有整体U(1)代对称性,所以,模型中的带电轻子质量矩阵和中微子Dirac质量矩阵是Fritzsch形式的.但是,中微子除了具有Dirac质量,一般还具有Majorana质量,在这种一般情况下, 关键词： 中微子质量 轻子味混合矩阵 左右对称模型 代对称性