119449106
Spin-flavor conversion and time variations of solar neutrino signals
Time variations of solarve-flux induced by spin-flavor conversion in the magnetic field of the sun have been studied. Several models of spatial and temporal distributions of the magnetic fields have been considered. The observed variations of the Ar-production rate in the Cl−Ar-experiment are shown to be not reproducible by these models. Unnaturally large values and fine tuned spatial structure of the fields are needed to explain the data.
3221192
Probing the seesaw mechanism with neutrino data and leptogenesis
In the framework of the seesaw mechanism with three heavy right-handed Majorana neutrinos and no Higgs triplets we carry out a systematic study of the structure of the right-handed neutrino sector. Using the current low-energy neutrino data as an input and assuming hierarchical Dirac-type neutrino masses mDi, we calculate the masses Mi and the mixing of the heavy neutrinos. We confront the inferred properties of these neutrinos with the constraints coming from the requirement of a successful baryogenesis via leptogenesis. In the generic case the masses of the right-handed neutrinos are highly hierarchical: Mi∝mDi2; the lightest mass is M1 ≈ 103−106 GeV and the generated baryon-to-photon ratio ηB10−14 is much smaller than the observed value. We find the special cases which correspond to the level crossing points, with maximal mixing between two quasi-degenerate right-handed neutrinos. Two level crossing conditions are obtained: mee ≈ 0 (1-2 crossing) and d12 ≈ 0 (2-3 crossing), where mee and d12 are respectively the 11-entry and the 12-subdeterminant of the light neutrino mass matrix in the basis where the neutrino Yukawa couplings are diagonal. We show that sufficient lepton asymmetry can be produced only in the 1-2 crossing where M1 ≈ M2 ≈ 108 GeV,M3 ≈ 1014 GeV and (M2−M1)/M210−5.
115887973
Solar neutrinos: Theoretical aspects
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.
118160727
Neutrino Oscillations In Matter With Varying Density
An alkali-metal benzoate is prepared besides benzyl alcohol from a contaminated benzyl benzoate reaction residue obtained in the oxidation of a monoalkyl-benzene compound with a gas containing molecular oxygen. The disclosed process provides for distillation of the contaminated benzyl benzoate in the presence of a basic substance and the resulting distillate is hydrolyzed using an alkali-metal base. In this way, the benzyl benzoate that previously could not be separated from certain tar components by distillation is converted into a pure alkali metal benzoate such as sodium benzoate, besides pure benzyl alcohol, so that a waste product that was previously useless is converted into useful substances.
118447115
COLORED SCALAR PARTICLES PRODUCTION IN pp-COLLISIONS AND POSSIBLE MASS LIMITS FOR SCALAR GLUONS FROM FUTURE LHC DATA
Cross sections of the colored scalar particle production in pp-collisions are calculated and differential and total cross sections of the corresponding parton subprocesses are obtained. The total cross section of scalar gluon production in pp-collisions at the LHC is estimated and the dominant decays of scalar gluons are discussed. The production cross section of scalar gluons F with masses mF ≲ 1300 GeV is shown to be sufficient for the effective production of these particles at the LHC.
119111785
Applications of FIESTA
Sector decomposition in its practical aspect is a constructive method used to evaluate Feynman integrals numerically. We present a new program performing the sector decomposition and integrating the expression afterwards. The program can be also used in order to expand Feynman integrals automatically in limits of momenta and masses with the use of sector decompositions and Mellin--Barnes representations. The program is parallelizable on modern multicore computers and even on multiple computers. Also we demonstrate some new numerical results for four-loop massless propagator master integrals.
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.
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.
2122861
Decoupling of heavy quarks in HQET
Decoupling of c-quark loops in b-quark HQET is considered. The decoupling coefficients for the HQET heavy-quark field and the heavy–light quark current are calculated with the three-loop accuracy. The last result can be used to improve the accuracy of extracting fB from HQET lattice simulations (without c-quark loops). The decoupling coefficient for the flavour-nonsinglet QCD current with n antisymmetrized γ-matrices is also obtained at three loops; the result for the tensor current (n = 2) is new.