Spontaneous SU(2) symmetry violation in the SU(2) L × SU(2) R × SU(4) electroweak model

A new approach to electroweak (EW) composite scalars is developed starting from the fundamental gauge interaction on high scale. The latter is assumed to have the group structure SU(2) _L × SU(2) _R × SU(4), where SU(4) is the Pati-Salam color-lepton group. The topological EW vacuum filled by instantons is explicitly constructed and the resulting equations for fermion masses exhibit spontaneous SU(2) flavor symmetry violation with possibility of very large mass ratios.     

Yukawa couplings in SU(3)×SU(2)×U(1)Y orbifold models

We analyze the Yukawa couplings of the first SU(3)×SU(2)×U(1)_Y orbifold models recently obtained. In these models the rank is naturally lowered due to the presence of a Fayet-Iliopoulos term associated with an “anomalous” U(1) in the four-dimensional theory. It is shown that the phenomenological viability of the models selects a favoured class of vacua. In particular, for the specific examples considered, some twisted fields with one moded oscillator acting, must acquire non-vanishing VEVs. However other possibilities may exist. We also find that all the baryon and lepton violating operators can be, in general, avoided in a completely natural way.     

Green function renormalization in SU(2)L ⊗ U(1) four-fermion model

Using the Dyson-Schwinger equation, the four-fermion Green functions in one-loop approximation to the SU(2)_L U(1) four-fermion model are found, as well as corrections to them. An expression is obtained for the collective field propagator in the one-loop approximation, and its regularization is performed. In the model under consideration, collective excitations are identified with a massless Goldstone field and a massive scalar field. It is shown that as a result of the reconstruction of the vacuum, one fermion (the analog of the neutrino) is massless, while the other (the analog of the electron), massive.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 19–23, January, 1984.     

Phenomenology of the hierarchical lepton mass spectrum in the flipped SU(5)×U(1) string model

A detailed phenomenological analysis of the lepton mass matrices and their implications in the low energy theory are discussed, within the recently proposed SU(5)×U(1) string model. The unification scale is highly constrained while the Yukawa couplings lie in a natural region. The flavour changing decays μ→eγ, μ→3e, μ→e are highly suppressed while the depletion in the in the flux of muon neutrinos reported by the Kamiokande is explained through ν_μ↔ν_τ oscillations.     

Search for chargino/neutralino pairs inpp-collisions in theSU(2) L ×SU(2) R ×U(1) B−L supersymmetric model

An extension of the supersymmetric standard model to the supersymmetricSU(2) _L ×SU(2) _R ×U(1) _B–L model with Higgs triplets is considered. We study in detail production of chargino and neutralino pairs at the LHCpp-collider of centre of mass energy TeV. A numerical analysis for different sets of mass values of charginos and neutralinos is considered. The analysis shows that the signatures are an increase of the total cross sections \sigma _T (pp \to \tilde \chi _2^ + \tilde \chi _1^ - ,\tilde \chi _2^0 \tilde \chi _1^0 + X) > \sigma _T (pp \to \tilde \chi _2^ + \tilde \chi _2^ - ,\tilde \chi _2^0 \tilde \chi _2^0 + X)$$ " align="middle" border="0"> , in the region of the transverse momentum,k _t . The analysis also shows that the experimental signatures depend essentially on the mixing matrix parameters of theL–R SUSY model.     

SU(3)_C×SU(2)_I×U(1)_Y复合轻子理论

假定HiggsYukawa耦合是宇称不守恒的唯一来源，通过取三代并引进超对称性，从而建立了一个SU（3）C×SU（2）I×U（1）Y复合轻子理论。     

On superstring-inspired SU(3) × SU(2) × (U(1))2 models with SO(10) unification

Alternative compactification of the heterotic superstring can give rise to a residual four-dimensional SO(10) gauge symmetry for the observable sector. We consider a model with gauge group SU(3) × SU(2) × (U(1))², resulting from the Hosotani breaking of SO(10), study its further gauge symmetry breaking and calculate the particle spectrum. We find that all breakings can occur close to the weak scale; the top mass lies preferentially between 40 and 60 GeV, the second Z boson mass is O(200–400) GeV. The sparticle spectrum is quite heavy, apart possibly from a light chargino, whose mass can be as light as O(30) GeV.     

An improved flipped SU(5)×U(1) model from the four-dimensional string

We discuss a four-dimensional string model whose effective field theory is a supersymmetric flipped SU(5)×U(1) GUT with the following properties.

• •- The quark and lepton mass matrices have a hierarchical structure and all Cabibbo-Kobayashi-Maskawa mixing angles can be non-zero.
• •- There is a natural splitting of Higgs doublets and triplets.
• •- A novel seesaw mechanism gives light left-handed neutrinos.
• •- The gauge group is reduced to the standard model SU(3)_C×SU(2)_L×U(1)_Y at a large mass scale close to M_P.

Extensive use is made of non-renormalizable superpotential couplings which may arise from couplings to identifiable massive modes, and are restricted by an R symmetry and the requirements of flatness is some field directions.     

SU(3)L×U(1)X模型和暗物质的新的候选者

提出了一个基于ＳＵ（３）Ｌ×Ｕ（１）Ｘ群的弱电相互作用模型．在该模型中,每一代轻子均包含两个中性粒子．计算了新的中性轻子（Ｎ粒子）的寿命,并估计了它的质量上限,从而说明Ｎ粒子可以看作暗物质的候选者．     

Inclusion of fermions in the locally SU(2) ⊗ U(1)-invariant model with dynamical symmetry breaking

It is shown that dynamic symmetry breaking in the locally SU(2) U(1)-invariant model with mixed inclusion of fermions in a four-fermion interaction leads to a situation in which one collective scalar field, representing the sum of all generations of fermion-antifermion pairs, acts as the total (one-loop) effective Lagrangian. Mass formulas are found for the scalar field and gauge vector fields. The effective Lagrangian obtained coincides in form with the standard Lagrangian in the Glashow-Weinberg-Salam theory of electroweak interactions.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 41–45, July, 1991.     

The Mass Bounds on Exotic Particles in an SU(3)L×U(1)X Model

We study an SU(3)_L×U(1)_X electroweak model. By requiring M²_Z1-M²_W/cos²θ_W to be less than experimental value we obtain a lower bound on Z' boson mass, M_Z' >600 GeV. The relation between M_Z' and M_U (M_V) then gives a lower bound on M_U (M_V):M_U (M_V)>490 GeV. From the constraint sin² θ_W(M_Z')<0.3, the upper bounds on M_Z' and M_U (M_V) are computed to be M_Z'<5.8×10⁴ TeV and M_U (M_V)<4.6×10⁴ TeV. We estimate further the K_L-K_S mass difference due to Z' exchange and try to use the result to obtain stronger lower bounds. On cosmological grounds we find that M_N<390 eV for T_f=2.3 GeV and M_N<740 eV for T_f=300 GeV.     

Structure of σ model in [1, 1] representation of SU(2) ⊗ SU(2) group

The spontaneous breakdown of symmetry of the-model in the [1, 1] representation of SU(2) SU(2) group is investigated. It is shown that the spontaneous breakdown is realized in all cases of squared mass ² in mass term in the Lagrangian ( ²>0, ²=0, ²<0), unlike the-model in [1/2, 1/2] representation, in which the spontaneous breakdown only for the case ²<0 manifests itself. Further, different but equivalent methods of obtaining the nonlinear realization for pions in the frame of an extended in such a way-model are demonstrated. Finally, it is sketched, that the obtained results can be generalized to all [N/2,N/2] representations of SU(2) SU(2) chiral group.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.On leave of absence from theDept. of Theoretical Physics, Comenius University, Bratislava, Czechoslovakia.     

SU(2) ×U(1) Gauge theory of bosonic and fermionic fields inS 3 ×R space-time

The tetradic Lorentz-gauge invariant formulation of the SU(2) × U(1) theory in S³ × R space-time is presented and the general gauge covariant Dirac-Klein-Gordon-Maxwell-Yang-Mills equations are derived. A direct comparison of these equations to those of the SU(2) × U(1) gauge theory on Minkowskian background points out major differences effectively induced by the minimally coupling to S³ × R gravity.     

Comment on the quark masses in the SU(5)×U(1) model derived from the 4D fermionic superstring

In this letter, the problems of the up-quark and neutrino mass matrix, as well as the lepton non-conservation are discussed within the N=1 supersymmetric SU(5)×U(1) model derived from the four-dimensional fermionic superstring.     

Chiral SU(2)×SU(2) model with infrared quark confinement

An SU(2)×SU(2) chiral quark model describing the properties and interaction of pions and scalar and vector mesons is considered. The confinement of quarks is introduced in the model by means of an infrared cut-off in the one-loop quark diagrams. This cutoff gives rise to the elimination of the unphysical thresholds of the quark-antiquark pair production. The π-a ₁ transitions are taken into account. The model conserves all low-energy theorems. The masses of mesons and the widths of the decays ρ → 2π and σ → 2π are calculated.     

A chiral SU(2)L⊗SU(2)R gauge model on the lattice

An explicitly chiral symmetric SU(2)_L⊗SU(2)_R model with a scalar doublet and a mirror pair of fermion doublets is investigated in lattice perturbation theory.     

SU(3)C×SU(2)I×U(1)Y Theory of Composite Leptons

Assuming Higgs Assuming coupling to be the only origin of parity non-conservation, an SU(3)_C×SU(2)_I×U(1)_Y theory of composite leptons is established in the Scheme of three generations and supersymmetry.     

Natural relations between the Cabibbo angle and quark masses in SU(2) L ×U(1) with four flavours

A complete classification of all possible natural relations between the Cabibbo angleΘ _c and quark masses is given which follow from an arbitrary horizontal symmetryH (discrete or continuous) and the standard gauge group SU(2) _L ×U(1) with four quark flavours. It is shown that such relations depend basically only on the dimensions of the fermion and Higgs representations and that they are therefore identical for allH with representations of the same dimensions and with the same Clebsch-Gordan series for the relevant Kronecker products. IfΘ _c depends on quark masses only, then eitherΘ _c ?m _d /m _s or \(\Theta _C \simeq m_d /\sqrt {2 m_s } \) . In particular, the phenomenologically successful relation \(\Theta _C \simeq \sqrt {m_d /m_s } \) cannot be obtained in a natural way in the 4-flavour SU(2) _L ×U(1) model for any horizontal symmetry.