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1.
Electroweak unification is obtained in anSU(7) model at a mass scale 3×1010M≦3×1016 GeV's, with left-right symmetric subgroups and sin2 θ w (M)=3/8. BelowM, the model reduces toSU(3) L ×SU(3) R , the flavor sector of the “trinification theory” of Glashow et al., or of theE 6 grand unified theory. This model predicts a natural massless neutrino, and fractionally charged leptons with masses in theM regime.  相似文献   

2.
A model based on theSU(2)L×SU(2)R×U(1)B−L gauge group is used to study the lepton recharging processe -μ+e +μ-. It should be possible to observe this process on a muon collider in the fixed-electron-target regime or the electron-beam regime. It is shown that the given process can be used to measure not only the characteristics of physical Higgs bosons, but also the parameters of neutrino oscillations. Grodno University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 83–88, November, 1998.  相似文献   

3.
The effective potential of the scalar field in theSU(5) model has extrema with symmetry:SU(5),SU(4)×U(1),SU(3)×SU(2)×U(1),SU(3)×[U(1)]2, [SU(2)]2×[U(1)]2. In our recent paper it was shown that theSU(4)×U(1) phase as well asSU(3)×SU(2)×U(1) phase were stable at the nonzero temperature in a vast region of parameters. In the present paper it is found that the [SU(2)]2×[U(1)]2 symmetric vacuum is unstable and theSU(3)×[U(1)]2 symmetric vacuum can be metastable in the certain interval of the temperature. Domains of the three phases:SU(4)×U(1),SU(3)×SU(2)×U(1),SU(3)×[U(1)]2-could co-exist in the early. Universe.  相似文献   

4.
We study the one-loop new physics effects to the CP even triple neutral gauge boson vertices γ γ Z, γ Z Z, Z Z γ and Z ZZ in the context of Little Higgs models. We compute the contribution of the additional fermions in Little Higgs models in the framework of direct product groups where [SU(2)×U(1)]2 gauge symmetry is embedded in SU(5) global symmetry and also in the framework of the simple group where SU(NU(1) gauge symmetry breaks down to SU(2) L ×U(1). We calculate the contribution of the fermions to these couplings when T parity is invoked. In addition, we re-examine the MSSM contribution at the chosen point of SPS1a′ and compare with the SM and Little Higgs models.  相似文献   

5.
A unification model of 4D gravity and SU(3)×SU(2)×U(1) Yang-Mills theory is presented. It is obtained from a Kaluza-Klein compactification of 8D quaternionic gravity on an internal CP 2=SU(3)/U(2) symmetric space. We proceed to explore the nonlinear connection formalism used in Finsler geometry to show how ordinary gravity in D=4+2 dimensions has enough degrees of freedom to encode a 4D gravitational and SU(5) Yang-Mills theory. This occurs when the internal two-dim space is a sphere S 2. This is an appealing result because SU(5) is one of the candidate GUT groups. We conclude by discussing how the nonlinear connection formalism of Finsler geometry provides an infinite hierarchical extension of the Standard Model within a six dimensional gravitational theory due to the embedding of SU(3)×SU(2)×U(1)⊂SU(5)⊂SU(∞).  相似文献   

6.
The kaon coupling constants at hyperon-nucleon vertices and the pion coupling constants at hyperon-hyperon vertices are calculated in the framework of the constant-cutoff approach to the CHK bound-state model of hyperons, where the postive-parity hyperons such as Λ, Σ, and ∑*=∑(1385) are theP-wave bound states of an antikaon and theSU(2) Skyrme soliton, while Λ* is theS-wave bound state. Meson coupling constants are defined as matrix elements of the meson-source terms between two single-baryon states following the method developed for resolving the Yukawa coupling problem in theSU(2) Skyrme soliton model. The magnitudes of the meson coupling constants are found to be close to those obtained using the complete Skyrme model and the phenomenological values.  相似文献   

7.
We present a supersymmetricSU(5)×U(1) model. This model has the following features. The gauge hierarchy is naturally generated by the quadratically divergent nature of the Fayet-IliopoulosD term. TheSU(5)×U(1) gauge symmetry breaks uniquely intoSU(3) W ×SU(2) c ×U(1) y at an energy scale of 1017–18GeV. The non-vanishing vacuum expectation value of an auxiliary field component ofU(1) gauge vector multiplet induces the breaking ofSU(2) W ×U(1) y . It gives a mass of 102–3GeV to scalar quarks and scalar leptons at the tree level. The renormalization group analysis shows that the color fine structure constant α C (M W ) becomes somewhat small and the Weinberg angle sin2θ W (M W ) somewhat too large in a simple version of the model.  相似文献   

8.
I present an argument, based on the topology of the universe, why there are three generations of fermions. The argument implies a preferred unified gauge group of SU(5), but with SO(10) representations of the fermions. The breaking pattern SU(5) → SU(3) × SU(2) × U(1) is preferred over the pattern SU(5) → SU(4) × U(1). On the basis of the argument one expects an asymmetry in the early universe microwave data, which might have been detected already.  相似文献   

9.
We suggest a quantum stabilization method for theSU(2) σ-model, based on the constant-cutoff limit of the cutoff quantization method developed by Balakrishnaet al., which avoids the difficulties with the usual soliton boundary conditions pointed out by Iwasaki and Ohyama. We investigate the baryon numberB = 1 sector of the model and show that after the collective coordinate quantization it admits a stable soliton solution which depends on a single dimensional arbitrary constant. We then study strong and electromagnetic properties of the Λ(1405) hyperon in the bound-state approach to theSU(3)-soliton model for the hyperons, withSU(3)-symmetry breaking. We calculate the strong coupling constantg Λ*NK; , the magnetic moment of Λ*, the mean square radii, and the radiative decay amplitudes. Finally we compare the present results with those obtained using other models and with the available empirical data. We show that there is a general qualitative agreement between our results and the results of other models and available empirical data, except for the Λ*πΣ coupling, which, as in the case of the complete Skyrme model, vanishes in the second-order approximation of the kaon fluctuations used in this work.  相似文献   

10.
The spontaneous generation of the chromomagnetic field at high temperature is investigated in a lattice formulation of the SU(2) gluodynamics. The procedure of studying this phenomenon is developed. Monte Carlo simulations of the free energy on the lattices 2 × 83, 2 × 163, and 4 × 83 at various temperatures are carried out. The creation of the field is indicated by means of the χ 2 analysis of the data set accumulating (5–10) × 106 Monte Carlo configurations. A comparison with the results of other approaches is done. The text was submitted by the authors in English.  相似文献   

11.
We present the bundle (Aff(3)Λ)(ℝ3), with a geometric Dirac equation on it, as a three-dimensional geometric interpretation of the SM fermions. Each (ℂΛ)(ℝ3) describes an electroweak doublet. The Dirac equation has a doubler-free staggered spatial discretization on the lattice space (Aff(3)ℂ)(ℤ3). This space allows a simple physical interpretation as a phase space of a lattice of cells. We find the SM SU(3) c ×SU(2) L ×U(1) Y action on (Aff(3)Λ)(ℝ3) to be a maximal anomaly-free gauge action preserving E(3) symmetry and symplectic structure, which can be constructed using two simple types of gauge-like lattice fields: Wilson gauge fields and correction terms for lattice deformations. The lattice fermion fields we propose to quantize as low energy states of a canonical quantum theory with ℤ2-degenerated vacuum state. We construct anticommuting fermion operators for the resulting ℤ2-valued (spin) field theory. A metric theory of gravity compatible with this model is presented too.  相似文献   

12.
With the hypothesis that all independent degrees of freedom of basic building blocks should be treated equally on the same footing and correlated by a possible maximal symmetry, we arrive at a 4-dimensional space-time unification model. In this model the basic building blocks are Majorana fermions in the spinor repre- sentation of 14-dimensional quantum space-time with a gauge symmetry GM4D = SO(1,3)×SU(32)×U(1)A×SU(3)F. The model leads to new physics including mirror particles of the standard model. It enables us to issue some fundamental questions that include: why our living space-time is 4-dimensional, why parity is not con- served in our world, how the stability of proton is, what the origin of CP violation is and what the dark matter can be.  相似文献   

13.
The one-loop effective potential of theSU(5) model is investigated both in high and low temperature approximation. We find the regions of values of coupling constants and temperatures where theSU(5), theSU(4)×U(1) and theSU(3)×SU(2)×U(1) symmetric states are metastable. A general method of such an investigation is proposed. We observe that the domain structure of the Universe with the simultaneous existence of the gauge symmetriesSU(4)×U(1) andSU(3)×SU(2)×U(1) in different domains could take place.  相似文献   

14.
We suggest a quantum stabilization method for theSU(2) σ-model, based on the constant-cutoff limit of the cutoff quantization method developed by Balakrishnaet al., which avoids the difficulties with the usual soliton boundary conditions pointed out by Iwasaki and Ohyama. We investigate the baryon numberB=1 sector of the model and show that after the collective coordinate quantization it admits a stable soliton solution which depends on a single dimensional arbitrary constant. We then study the radiative decays ofJ π=3/2+ baryons using the constant-cutoff approach to theSU(3) collective treatment of the Skyrme model for hyperons. Thus we evaluate the widths and E2/M1 ratios, showing that there is a general qualitative agreement with the results obtained using the complete Skyrme model, as well as the nonrelativistic quark model and quenched lattice model, for the total widths.  相似文献   

15.
The recently discovered narrow peaks (theψ-particles) in e+e system at 3.105 and 3.695 GeV are interpreted as hadrons in a broken SU4 symmetry scheme. A new additional additive quantum number, parachargeZ, is combined with the usual SU3 quantum numbers in the group SU4. Theψ (3.1) is assigned to a near ideally mixed151 multiplet of vector mesons (containing theρ) as theI=Y=0, charge conjugationC=−combination ofZ=±1.members. Theψ (3.7) is assigned correspondingly to another mixed151 multiplet containing theρ′ (1600). The hadronic electromagnetic interactions are modified by the addition of (non-minimal) anomalous pieces that can changeZ. The decays of theψ-particles are discussed. New enlarged SU4 multiplets of other hadrons are proposed. Tests of our scheme are put forward. The most crucial test will be the observation of two rather broad resonances in e+ e collisions with masses around 4.2 GeV and 5.1 GeV. Another prediction is the presence of energetic photons in the decays of theψ-particles. Important results concerning the recently observed phenomena in the process e+e→hadrons follow in this scheme.  相似文献   

16.
Electroweak breaking and the supersymmetric particle spectrum are discussed in superstring theories where the gauge group after compactification isSO(10)×E s , and where the gauge symmetry after flux breaking isSU(3)×SU(2)×SU(2)×U(1).  相似文献   

17.
Absolute spectral luminosity from an O2–O2(a)-H2O gas flow formed by a chemical singlet oxygen generator was measured at 600–800 and 1230–1310 nm wavelengths. The results were used to determine the rate constants for O2(a, 0) + O2(a, 0) → O2(X, 0) + O2(X, 0) + hν (λ = 634 nm) and O2(a, 0) + O2(a, 0) → O2(X, 1) + O2(X, 0) + hν (λ = 703 nm) collision-induced emission ((6.72 ± 0.8) × 10−23 and (7.17 ± 0.8) × 10−23 cm3/s, respectively).  相似文献   

18.
Possible proton decays in theSU(4) C ×SU(2) L ×SU(2) R unification model are discussed. There are some characteristics in the decay products, which are different from those in the standardSU(5) orSO (10) model, in certain cases.  相似文献   

19.
We have studied the magnetic aftereffects in the Ni x Fe3−x−ΔO4 system, for 0≦x≦1 and 10−5≦Δ≦2×10−1, between 80 and 500 K. The samples were obtained by sintering at 1400°C in an appropriate gas atmosphere. The measurements are based on the deviation from equilibrium that is produced in a Maxwell-Wien bridge when the self-induction of a coil with ferrite core varies because of the phenomenon of magnetic aftereffects. The numerical analysis of the results shows the presence of relaxation processes at 300 K (III), 330 K (IIa), and above 500 K (I). The Processes III and IIa are related to the concentration of nickel,x, and of vacancy, Δ. It is seen that the IIa peak can be attributed to a process of diffusion of Ni ions in the spinel lattice by means of vacancies on octahedral sites.  相似文献   

20.
Jogesh C. Pati 《Pramana》2004,62(2):513-522
Evidence in favor of supersymmetric grand unification including that based on the observed family multiplet-structure, gauge coupling unification, neutrino oscillations, baryogenesis, and certain intriguing features of quark-lepton masses and mixings is noted. It is argued that attempts to understand (a) the tiny neutrino masses (especially Δm 2(v 2 – v3)), (b) the baryon asymmetry of the Universe (which seems to need leptogenesis), and (c) the observed features of fermion masses such as the ratiom b/mτ, the smallness ofV cb and the maximality of seem to select out the route to higher unification based on an effective string-unifiedG(224) =SU(2)L ×SU(2)R ×SU(2)c orSO(10)-symmetry that should be operative in 4D, as opposed to other alternatives. A predictiveSO(10)/G(224)-framework possessing supersymmetry is presented that successfully describes the masses and mixings of all fermions including neutrinos. It also accounts for the observed baryon asymmetry of the Universe by utilizing the process of leptogenesis, which is natural to this framework. It is argued that a conservative upper limit on the proton lifetime within thisSO(10)/G(224)-framework, which is so far most successful, is given by x 1034 years. This in turn strongly suggests that an improvement in the current sensitivity by a factor of five to ten (compared to SuperK) ought to reveal proton decay. Implications of this prediction for the next-generation nucleon decay and neutrino-detector are noted.  相似文献   

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