18923436
Boron neutrino flux and the MSW solution of the solar neutrino problem
There are large uncertainties in the predictions of the boron neutrino flux from the Sun which cannot be considered as being of purely statistical origin. We treat the magnitude of this flux, {Phi}{sub B}, as a parameter to be found from experiment. The properties of the, MSW solution to the solar neutrino problem for different values of {Phi}{sub B} are studied. Present, data give the bounds: 0.38 5 MeV close to 1. We comment on the possibility to measure the neutrino parameters and the original boron neutrino flux in future experiments.« less
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.
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.
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.
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.
18167542
Fermionic Decays of Scalar Leptoquarks and Scalar Gluons in the Minimal Four-Color Symmetry Model
Fermionic and weak decays of the scalar leptoquarks S = S1(+), S1(−), and Sm and the scalar gluons F = F1 and F2 predicted by the minimal model involving four-color symmetry and the Higgs mechanism of quark-and lepton-mass splitting are considered. The widths and the branching ratios are calculated for these decays, and the results are analyzed versus the couplings and masses of decaying particles. It is shown that, at relatively small mass splittings Δm within scalar doublets (Δm mW, the weak decays S → S′W and F → F’W compete with the above fermionic decays. In the case of mS < mt, the processes S1(+) → clj+, S1(−) → vi\(\tilde b\), Sm → blj+, and Sm → c\(\tilde \nu \)j, whose total branching ratios are Br(S1(+) → cl+) ≈ Br(S1(−) → v\(\tilde b\)) ≈ 1, Br(Sm → bl+) ≈ 0.9, and Br(Sm → c\(\tilde \nu \)) ≈ 0.1, appear to be dominant decays of scalar leptoquarks. Searches for these decays at LHC and the Tevatron are of interest.
118835200
THE CHIRAL COLOR SYMMETRY OF QUARKS AND G′-BOSON CONTRIBUTIONS TO CHARGE ASYMMETRY IN $t \bar t$-PRODUCTION AT THE LHC AND TEVATRON
The contributions of G′-boson predicted by the chiral color symmetry of quarks to the charge asymmetry in -production at the LHC and to the forward–backward asymmetry in -production at the Tevatron are calculated and analyzed in dependence on two free parameters of the model, the G′ mass mG′ and mixing angle θG. The mG′ - θG regions of 1 σ consistency with the CMS data on the cross-section and on the charge asymmetry are found and compared with those resulted from the CDF data on the cross-section and on the forward–backward asymmetry of -production at the Tevatron with account of the current SM predictions for .
2085821
Applying Mellin-Barnes technique and Gröbner bases to the three-loop static potential
The Mellin‐Barnes technique to evaluate master integrals and the algorithm called FIRE to solve IBP relations with the help of Grobner bases are briefly revie wed. In FIRE, an extension of the classical Buchberger algorithm to construct Grobner ba ses is combined with the well-known Laporta algorithm. It is explained how both techniques are used when evaluating the three-loop correction to the static QCD quark potential. First results are presented: the coefficients of n 3 and n 2 , where nl is the number of light quarks.
123279554
Chiral color quark symmetry and possible constraints on the G′-boson mass from tevatron and LHC data
A gauge model featuring a chiral color symmetry of quarks was considered, and possible manifestations of this symmetry in proton-antiproton and proton-proton collisions at the Tevatron and LHC energies were studied. The cross section $$\sigma _{t\bar t}$$ for the production of $$t\bar t$$ quark pairs at the Tevatron and the forward-backward asymmetry $$A_{FB}^{p\bar p}$$ in this process were calculated and analyzed with allowance for the contributions of the G′-boson predicted by the chiral color symmetry of quarks, the G′-boson massmG′ and the mixing angle θG being treated as free parameters of the model. Limits on mG′ versus θG were studied on the basis of data from the Tevatron on $$\sigma _{t\bar t}$$ and $$A_{FB}^{p\bar p}$$, and the region compatible with these data within one standard deviation was found in the mG′-θG plane. The region ofmG′-mass values that is appropriate for observing the G′-boson at LHC is discussed.
55043207
DESIGN OF THE NUCLOTRON BOOSTER IN THE NICA PROJECT
NICA is the new complex being constructed on the JINR aimed to provide collider experiments with ions up to uranium at energy of 3.5x3.5 GeV/u. The NICA layout includes Electron String Ion Source, 6.2 Mev/u linac, 600 MeV/u booster synchrotron, upgraded Nuclotron and ion collider with average luminosity of 10 27 cm -2 s -1 . The main goals of the Booster are the following: accumulation of 4·10 9 Au 32+ ions; acceleration of the heavy ions up to energy required for effective stripping; forming of the required beam emittance with electron cooling system. The present layout makes it possible to place the Booster having 211 m circumference and four fold symmetry lattice inside the yoke of the Synchrophasotron (shut down in 2002). The features of this booster, the requirement to the main synchrotron systems and their parameters are presented in this paper.