119045478
Neutrino Oscillations in Vacuum and Matter
Neutrino oscillations in vacuum have been discussed first by Pontecorvo [1]. Strong transformations of mixed neutrinos in matter [2–4] have three aspects: 
 
1) 
 
The detection of cosmic neutrinos is known to be a unique channel of information about the structure, energetics and evolution of stars as well as galaxies and the Universe. Experimental techniques for their detection are now developed very actively and first results have been obtained. The interpretation of the data should take into account possible effects of resonant neutrino oscillations: neutrinos produced in central regions of stars cross large layers of matter and the properties of neutrino fluxes may be changed drastically. 
 
 
 
 
2) 
 
Changing of neutrino fluxes due to resonant oscillations depend on the difference of mass squared (∆m 2 = m 2 1 − m 2 2) and on neutrino mixing (sin2 2λ) in a quite definite manner. Consequently, the search for effects of resonant oscillations involves measuring ∆m 2 and sin2 2λ. Moreover, the method is sensitive to regions of ∆m 2 vs. sin2 2λ which are far beyond the possibilities of terrestrial experiments. 
 
 
 
 
3) 
 
If effects of resonant oscillations are found (or if ∆m 2 and sin2 2λ are fixed in other experiments), then it will be possible to make definite conclusions about the density profiles which are crossed by neutrinos.
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.
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.
18492548
Pontecorvo's original oscillations revisited
Abstract We show that a left-handed neutrino ν L can oscillate into its CPT -conjugate state ν R with maximal amplitude, in direct analogy with K 0 − K 0 oscillations. Peculiarities of such oscillations under different conditions are studied.
115887973
Solar neutrinos: Theoretical aspects
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.
120006374
Contributions of scalar leptoquarks to the cross sections for the production of quark-antiquark pairs in electron-positron annihilation
AbstractThe contributions of scalar-leptoquark doublets to the cross sections 
$$\sigma _{Q\tilde Q} $$
, for the production of quark-antiquark pairs in electron-positron annihilation are calculated within the minimal model based on the four-color symmetry of quarks and leptons. These contributions are analyzed versus the scalar-leptoquark masses and the mixing parameters of the model at colliding-particle energies in the range 250–1000 GeV. It is shown that the contributions in question are of greatest importance for processes leading to t-quark production. In particular, it is found that, with allowance for the contribution of the scalar leptoquark of charge 5/3 and mass in the range 250–500 GeV, the cross section 
$$\sigma _{t\tilde t} $$
 calculated at a mixing-parameter value of kt ∼ 1 may be severalfold larger than the corresponding cross section 
$$\sigma _{t\tilde t}^{(SM)} $$
 within the Standard Model. The possibility of setting constraints on the scalar-leptoquark masses and on the mixing parameters by measuring such contributions at future electron-positron colliders is indicated.
14044114
Expansion by regions: revealing potential and Glauber regions automatically
When performing asymptotic expansions using the strategy of expansion by regions, it is a non-trivial task to find the relevant regions. The recently published Mathematica code asy.m automates this task, but it has not been able to detect potential regions in threshold expansions or Glauber regions. In this work we present an algorithm and its implementation in the update asy2.m which also reveals potential and Glauber regions automatically.
17035129
CHIRAL COLOR SYMMETRY AND POSSIBLE G′-BOSON EFFECTS AT THE TEVATRON AND LHC
A gauge model with chiral color symmetry is considered and possible effects of the color G′-boson octet predicted by this symmetry are investigated in dependence on two free parameters, the mixing angle θG and G′ mass mG′. The allowed region in the mG'–θG plane is found from the Tevatron data on the cross section and forward–backward asymmetry of the production. The mass limits for the G′-boson are shown to be stronger than those for the axigluon. A possible effect of the G′-boson on the production at the LHC is discussed and the mass limits providing for the G′-boson evidence at the LHC are estimated in dependence on θG.
120951273
Parameters S, T, and U of radiative corrections and masses of scalar leptoquarks in the minimal model featuring four-color symmetry
The contributions to the parameters S, T, and U of radiative corrections are discussed within the minimal model featuring four-color symmetry of the Pati-Salam type. A numerical analysis of these contributions is given for the Higgs mechanism of mass generation for scalar leptoquarks and the simplest version of scalar-leptoquark mixing. It is shown that up-to-date experimental data on S, T, and U are compatible with the existence of relatively light scalar leptoquarks (of masses about 1 TeV or below), still lighter scalar leptoquarks (of masses below 1 TeV) improving the agreement of theoretical results with experimental data on S, T, and U.
118529983
ON MASS LIMIT FOR CHIRAL COLOR SYMMETRY G'-BOSON FROM TEVATRON DATA ON $t\bar t$ PRODUCTION
The contributions of G'-boson predicted by the chiral color symmetry of quarks to the cross section $\sigma_{t\bar{t}}$ and to the forward–backward asymmetry $A_{{\rm FB}}^{p \bar p}$ of $t\bar{t}$ production at the Tevatron are calculated with account of the difference of the strengths of the $\bar q q G$ and $\bar q q G^\prime$ interactions. The results are analyzed in dependence on two free parameters of the model, the mixing angle θG and G' mass mG'. The G'-boson contributions to $\sigma_{t\bar{t}}$ and $A_{{\rm FB}}^{p \bar p}$ are shown to be consistent with the Tevatron data on $\sigma_{t\bar{t}}$ and $A_{{\rm FB}}^{p \bar p}$, the allowed region in the mG' - θG plane is discussed and around mG' = 1.2 TeV, θG = 14° the region of 1σ consistency is found.