14713509
Neutrino mixing and quark-lepton complementarity
As a result of the identification of the solution to the solar neutrino problem, a rather precise relation ${\ensuremath{\theta}}_{\mathrm{s}\mathrm{u}\mathrm{n}}+{\ensuremath{\theta}}_{C}=\ensuremath{\pi}/4$ between the leptonic 1-2 mixing angle ${\ensuremath{\theta}}_{\mathrm{s}\mathrm{u}\mathrm{n}}$ and the Cabibbo angle has emerged. It would mean that the lepton and the quark mixing angles add up to the maximal, suggesting a deep structure by which quarks and leptons are interrelated. We refer to the relation as ``quark-lepton complementarity'' (QLC) in this paper. We formulate general conditions under which the QLC relation is realized. We then present several scenarios which lead to the relation and elaborate on phenomenological consequences which can be tested by the future experiments. We also discuss implications of the QLC relation for the quark-lepton symmetry and the mechanism of neutrino mass generation.
119540272
Self-induced spectral splits in supernova neutrino fluxes
In the dense-neutrino region above the neutrino sphere of a supernova (r < or approx. 400 km), neutrino-neutrino refraction causes collective flavor transformations. They can lead to 'spectral splits' where an energy E{sub split} splits the transformed spectrum sharply into parts of almost pure but different flavors. Unless there is an ordinary MSW resonance in the dense-neutrino region, E{sub split} is determined by flavor-lepton number conservation alone. Spectral splits are created by an adiabatic transition between regions of large and small neutrino density. We solve the equations of motion in the adiabatic limit explicitly and provide analytic expressions for a generic example.
115887973
Solar neutrinos: Theoretical aspects
59164737
Recent developments in neutrino phenomenology
The first phase of studies of the neutrino mass and mixing is essentially over. The outcome is the discovery of non-zero neutrino mass and determination of the dominant structure of the lepton mixing matrix. In some sense this phase was very simple, and nature was very collaborative with us: Two main effects - the vacuum oscillations and the adiabatic conversion in matter (the MSW-effect) - provide complete interpretation of the experimental results. Furthermore, with the present accuracy of measurements the $3\nu-$mixing analysis is essentially reduced to the $2\nu$ consideration. I will present a concise and comprehensive description of this first phase. The topics include: (i) the concept of neutrino mixing in vacuum and matter; (ii) physics of the oscillations and adiabatic conversion; (iii) the experimental evidences of the flavor transformations and determination of the oscillation parameters. Some implications of the obtained results are discussed. Comments are given on the next phase of the field that will be much more involved.
31519375
Multiple spectral splits of supernova neutrinos.
Collective oscillations of supernova neutrinos swap the spectra f(nu(e))(E) and f(nu[over ](e))(E) with those of another flavor in certain energy intervals bounded by sharp spectral splits. This phenomenon is far more general than previously appreciated: typically one finds one or more swaps and accompanying splits in the nu and nu[over ] channels for both inverted and normal neutrino mass hierarchies. Depending on an instability condition, swaps develop around spectral crossings (energies where f(nu(e))=f(nu(x)), f(nu[over ](e))=f(nu[over ](x)) as well as E-->infinity where all fluxes vanish), and the widths of swaps are determined by the spectra and fluxes. Washout by multiangle decoherence varies across the spectrum and splits can survive as sharp spectral features.
125260667
SLIDING SINGLET AND STABILITY OF THE MASS HIERARCHY. (IN RUSSIAN)
11320046
Bounds on scalar leptoquark and scalar gluon masses from current data on S, T, U
The contributions into radiative correction parameters S, T, U from scalar leptoquark and scalar gluon doublets are investigated in the minimal four color symmetry model. It is shown that the existence of the relatively light scalar leptoquarks and scalar gluons (with masses of order of 1 TeV or less) is consistent with the current experimental data on S, T, U and the more light particles (with masses below 400 GeV) improve the fit. In particular, the lightest scalar leptoquarks with masses below 300 GeV are consistent with the current data on S, T, U at $\chi^2 < 3.1(3.2)$ for $m_H=115(300) GeV$ in comparison with $\chi^2 = 3.5(5.0)$ in the Standard Model. The lightest scalar gluon in this case is expected to lie below $ 850(720) GeV.$ The possible significance of such particles in the t-quark physics at LHC is emphasized and their effect on the gauge coupling constant unification is briefly discussed.
120793699
Quark masses from low-energy moments of heavy-quark current correlators
We present an update of the determination of charm- and bottom-quark masses from the lowenergy expansion of the vacuum polarization function in combination with experimental data for R(s). This analysis leads to the most precise determination of th e masses of the charm and bottom quarks: mc(3 GeV) = 986(13) MeV, mb(mb) = 4163(16) MeV.
118758893
Minimal four-color model with quark-lepton symmetry and constraints on the Z{prime}-boson mass
A minimal model with quark-lepton symmetry is considered. This model, which describes unified electroweak and strong interactions, is a minimal extension of the standard model that involves four-color symmetry of quarks and leptons. Predicted relations between the masses of leptoquarks and W{sup +-}, Z, and Z{prime} bosons are studied, and the contributions of an additional Z{prime} boson to the cross sections for e{sup +}e{sup -} annihilation and the asymmetry A{sub FB} at TRISTAN and LEP200 energies are analyzed. Experimental data are shown to be consistent with the existence of a relatively light Z{prime} boson associated with four-color quark-lepton symmetry. 12 refs., 3 figs., 1 tab.
116859657
Scalar Leptoquark Contributions into $l_i\to l_j\gamma$ Processes
The contributions of scalar leptoquarks in lepton flavor violating (LFV) processes of type $l_i\to l_j \gamma$ are investigated in frame of the minimal model with the four color symmetry and Higgs mechanism of quark and lepton mass generation. It is shown that experimental data on the decays $\mu\to e \gamma$, $\tau \to \mu \gamma$, $\tau\to e \gamma$ allow the existence of light scalar leptoquarks of type under consideration, with masses of order 1 TeV or below.
120577993
Asymptotic behavior of amplitudes for longitudinal-leptoquark processes and structure of the scalar sector in the minimal model involving four-color symmetry
Within the minimal model based on the four-color symmetry of quarks and leptons of the Pati-Salam type, the asymptotic behavior of amplitudes for processes involving longitudinal leptoquarks (and W or Z′ bosons) is investigated, together with the mechanism according to which the growth of these amplitudes at high energies is suppressed by scalar fields. It is shown that, within the Higgs mechanism of mass generation and of the mass splitting of quarks and leptons, the four-color symmetry of quarks and leptons requires that scalar-leptoquark doublets, scalar-gluon doublets, and an extra color-singlet scalar doublet exist in addition to the standard Higgs doublet.