Resonant spin-flavor precession constraints on the neutrino parameters and the twisting structure of the solar magnetic fields from the solar neutrino data

Resonant spin-flavor precession (RSFP) scenario with twisting solar magnetic fields has been confronted with the solar neutrino data from various ongoing experiments. The anticorrelation apparent in the Homestake solar neutrino data has been taken seriously to constrain (Δ m ² ,φ′) parameter space and the twisting profiles of the magnetic field in the convective zone of the Sun. The twisting profiles, thus derived, have been used to calculate the variation of the neutrino detection rates with the solar magnetic activity for the Homestake, Super-Kamiokande and the gallium experiments. It is found that the presence of twisting reduces the degree of anticorrelation in all the solar neutrino experiments. However, the anticorrelation in the Homestake experiment is expected to be more pronounced in this scenario. Moreover, the anticorrelation of the solar neutrino flux emerging from the southern solar hemisphere is expected to be stronger than that for the neutrinos emerging from the northern solar hemispheres.     

One model for magnetic solar neutrino interactions,cosmological neutrino decays,and new particle resonant production by interactions of neutrinos from Cygnus X-3

Standard model extensions which include a charged, weak-singlet scalar particle can induce an electron-neutrino magnetic moment large enough to implement the Voloshin-Vysotski-Okun solution to the solar neutrino problem and observed anticorrelation of sunspots and neutrino flux. The resonant production and decay of such a charged scalar particle by neutrinos from ultra-high energy point sources of cosmic rays such as Cygnus X-3 has been discussed in the literature as a possible source of an anomalous muon signal in deep underground detectors. We argue here that there are versions of the charged scalar model which simultaneously can accommodate the above phenomena and in addition predict a radiative neutrino decay whose lifetime is about 10²⁴ s. This value is consistent with that needed for a dark-matter neutrino of about 30 eV mass to yield a flux of UV photons which could explain several puzzling observations of H_α emission from the galactic disk and from the intergalactic HI cloud in Leo.     

MHD origin of density fluctuations deep within the Sun and their influence on neutrino oscillation parameters in LMA MSW scenario

We analyze helioseismic waves near the solar equator in the presence of magnetic fields deep within the solar radiative zone. We find that reasonable magnetic fields can significantly alter the shapes of the wave profiles for helioseismic g modes. They can do so because the existence of density gradients allows g modes to resonantly excite Alfvén waves, causing mode energy to be funneled along magnetic field lines, away from the solar equatorial plane. The resulting waveforms show comparatively sharp spikes in the density profiles at radii where these resonances take place. Such matter density waves with known spatial structure are substituted as a matter density noise into the 2×2 Schrödinger equation for ν _e,π neutrinos oscillating within the Sun. Then we reexamine the sensitivity of solar neutrino oscillations to noise in the solar interior using the best current estimates of neutrino properties. Our results show that the measurement of neutrino properties at KamLAND provides new information about fluctuations in the solar environment on scales to which standard helioseismology constraints are largely insensitive. We also show how the determination of neutrino oscillation parameters from a combined fit of KamLAND and solar data depends strongly on the magnitude of solar density fluctuations.     

Topological geometrodynamics and the solar neutrino problem

A solution of the solar neutrino problem based on certain differences between T(opological) G(eometro) D(ynamics) and the standard model of the electroweak interactions is proposed. First, TGD predicts the existence of a right-handed neutrino inert with respect to ordinary electroweak interactions. Second, the generalization of the massless Dirac equation contains terms mixing differentM ⁴ chiralities, unlike the ordinary massless Dirac equation. This and the observation of anticorrelations of the solar neutrino flux with sunspot number suggest that solar neutrinos are transformed to right-handed neutrinos on the convective zone of the Sun. Third, the compactness ofCP ₂ implies topological field quantization: space-time decomposes into regions, topological field quanta, characterized by a handful of vacuum quantum numbers. In particular, there are topological obstructions for the smooth global imbeddings of magnetic fields and the decomposition of the solar magnetic field into flux tubes is predicted. Finally, every electromagnetically neutral mass distribution is accompanied by a long-rangeZ ⁰ vacuum field. If the vacuum quantum numbers inside the flux tubes of the solar magnetic field are considerably smaller than in the normal phase, theZ ⁰ electric force becomes strong and implies Thomas precession for the spin of the lefthanded component of the neutrino. As a consequence, left-handed neutrinos are transformed to right-handed ones and the process is irreversible, since righthanded neutrinos do not couple toZ ⁰.     

SNO results and neutrino magnetic moment solution to the solar neutrino problem

We have analysed the solar neutrino data obtained from chlorine, gallium and Super-Kamiokande (SK) experiments (1258 days) and also the new results that came from Sudbury Neutrino Observatory (SNO) charge current (CC) and elastic scattering (ES) experiments considering that the solar neutrino deficit is due to the interaction of neutrino transition magnetic moment with the solar magnetic field. We have also analysed the moments of the spectrum of scattered electrons at SK. Another new feature in the analysis is that for the global analysis, we have replaced the spectrum by its centroid.     

Renormalization of seesaw neutrino masses in the standard model with two-Higgs doublets

Using the theoretical ambiguities inherent in the seesaw mechanism, we derive the new analytic expressions for both quadratic and linear seesaw formulae for neutrino masses at low energies, with either up-type quark masses or charged lepton masses. This is possible through full radiative corrections arising out of the renormalizations of the Yukawa couplings, the coefficients of the neutrino-mass-operator in the standard model with two-Higgs doublets, and also the QCD-QED rescaling factors below the top-quark mass scale, at one-loop level. We also investigate numerically the unification of top-b-τ Yukawa couplings at the scale M ₁=0.59×10⁸ GeV for a fixed value of tan β=58.77, and then evaluate the seesaw neutrino masses which are too large in magnitude to be compatible with the presently available solar and atmospheric neutrino oscillation data. However, if we consider a higher but arbitrary value of M ₁=0.59×10¹¹ GeV, the predictions from linear seesaw formulae with charged lepton masses, can accommodate simultaneousely both solar atmospheric neutrino oscillation data.     

Solar neutrinos. Astrophysical aspects

This paper is a short pedagogical introduction to some aspects of the solar neutrino problem. The basic attention is concentrated on a qualitative consideration of the pp and CNO reactions responsible for hydrogen burning in the Sun, starting from an elementary derivation of the formula for the non-resonant thermonuclear reaction rate. We outline the physical content of the standard solar models, the problem of chemical composition of the Sun, expected neutrino energy spectrum, radial distributions of the neutrino fluxes in the Sun, and uncertainties in the predicted neutrino event rates.     

Majorana neutrino transition magnetic moment in a variant of Zee model with horizontal symmetry

A SU(2) _H symmetric variant of Zee model of lepton flavor violation is presented and is shown to lead to neutrino transition magnetic moment of the order required to explain the solar neutrino deficit and the possible anticorrelation of solar neutrino flux with sunspot activity via VVO mechanism. The use of horizontal symmetry leads to totally degenerate neutrino states which may be combined to form a ZKM Dirac neutrino with naturally small mass.     

Restrictions on the neutrino magnetic dipole moment

We examine mechanisms for producing neutrino magnetic moments from a wide class of particle theories which are extensions of the standard model. We show that it is difficult to naturally obtain a moment greater than ∼ 10⁻² electron Bohr magnetons. Thus models of phenomena requiring moments of order ∼ 10⁻¹⁰ magnetons, such as those proposed as a resolution to the solar neutrino puzzle, are in conflict with current perceptions in particle physics.     

Resonant neutrino spin-flip transitions in twisting magnetic fields

We examine here in detail the dynamics of neutrino spin-flip transitions in twisting magnetic fields. The properties of various resonant conversions induced by field rotation are considered. The suppression factors for solarv _eL due to spin-flip transitions in twisting magnetic fields are calculated, and possible implications for solar neutrino experiments are discussed.     

Neutrino observations from the sudbury neutrino observatory

Neutrino observations from the Sudbury Neutrino Observatory are presented from preliminary analyses. Based on energy, direction and location, the data in the region of interest appear to be dominated by ⁸B solar neutrinos, detected by the charged current reaction on deutrium and elastic scattering from electrons, with very little background. Measurements of radioactive backgrounds indicate that the measurement of all active neutrino types via the neutral current reaction on deuterium will be possible with small systematic uncertainties. Results for the fluxes observed with these reactions will be provided when further calibrations have been completed.     

Neutrino masses,mixings, and FCNC’s in an <Emphasis Type="Italic">S</Emphasis><Subscript>3</Subscript> flavor symmetric extension of the standard model

By introducing threeHiggs fields that are SU(2) doublets and a flavor permutational symmetry, S ₃, in the theory, we extend the concepts of flavor and generations to the Higgs sector and formulate a Minimal S ₃-Invariant Extension of the Standard Model. The mass matrices of the neutrinos and charged leptons are re-parameterized in terms of their eigenvalues, then the neutrino mixing matrix, V _PMNS, is computed and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained in excellent agreement with the latest experimental data. We also compute the branching ratios of some selected flavor-changing neutral current (FCNC) processes, as well as the contribution of the exchange of neutral flavor-changing scalars to the anomaly of the magnetic moment of the muon, as functions of the masses of charged leptons and the neutral Higgs bosons. We find that the S ₃ × Z ₂ flavor symmetry and the strong mass hierarchy of the charged leptons strongly suppress the FCNC processes in the leptonic sector, well below the present experimental bounds by many orders of magnitude. The contribution of FCNC’s to the anomaly of the muon’s magnetic moment is small, but not negligible.     

Self-energy operator of a massive neutrino in an external magnetic field

The effect of the magnetic field on the properties of a massive neutrino is analyzed. A general expression is derived in terms of the self-energy operator of the neutrino in an external magnetic field of arbitrary strength. This expression is valid for any relationship between the masses of the neutrino, a charged lepton, and a W-boson. An anomalous magnetic moment of a standard neutrino is investigated. The probability of massive neutrino decay into a W-boson and a charged lepton is calculated for various values of the magnetic field strength.     

Progress in neutrino oscillation searches and their implications

Neutrino oscillation, in which a given flavor of neutrino transforms into another is a powerful tool for probing small neutrino masses. The intrinsic neutrino properties involved are neutrino mass squared difference Δm ² and the mixing angle in vacuum θ. In this paper I will summarize the progress that we have achieved in our search for neutrino oscillation with special emphasis on the recent results from the Sudbury Neutrino Observatory (SNO) on the measurement of solar neutrino fluxes. I will outline the current bounds on the neutrino masses and mixing parameters and discuss the major physics goals of future neutrino experiments in the context of the present picture.     

A gut solution to the solar neutrino problem

Within the supersymmetric flipped SU(5)×U(1) model, we propose a mechanism for realization of the Voloshin-Vysotsky-Okun solution to the solar neutrino problem by attributing a large magnetic moment to the electron neutrino, as required to explain the solar neutrino data.     

Resonant neutrino oscillations and the neutrino signature of supernovae

We examine the effects of resonant neutrino oscillations, proposed as a solution to the solar neutrino puzzle, on the neutrino signature of a Type II supernova. We find that, for parameters corresponding to an adiabatic conversion of most of the ⁸B neutrino flux, the supernova neutrino signal in a water-Čerenkov detector is altered in the following way: (1) The isotropic-to-directional event ratio increases; (2) The short time scale neutronization burst signal decreases by a factor 7, perhaps rendering it unobservable. Detection of these changes would allow one to distinguish between neutrino oscillations and solar model alterations as solutions to the solar neutrino problem. We also note that mixing of the higher energy ν_μ and ν_r's to ν_e's will enhance detection of the thermally produced ν-flux.     

Constraining the neutrino magnetic moment with antineutrinos from the sun

We discuss the impact of different solar neutrino data on the spin-flavor-precession (SFP) mechanism of neutrino conversion. We find that, although detailed solar rates and spectra allow the SFP solution as a subleading effect, the recent KamLAND constraint on the solar antineutrino flux places stronger constraints on this mechanism. Moreover, we show that for the case of random magnetic fields inside the Sun, one obtains a more stringent constraint on the neutrino magnetic moment down to the level of mu(nu)< or = few x 10(-12)mu(B), similar to bounds obtained from star cooling.     

Probing the neutrino mass matrix in next-generation neutrino oscillation experiments

We review the current status of the neutrino mass and mixing parameters needed to reconstruct the neutrino mass matrix. A comparative study of the precision in the measurement of oscillation parameters expected from the next-generation solar, atmospheric, reactor-and accelerator-based neutrino experiments is presented. We discuss the potential of 0νββ experiments in determining the neutrino mass hierarchy and the importance of a better ϑ ₁₂ measurement for it. The text was submitted by the author in English.     

Neutrino–Electron Processes in a Magnetic Field and Their Crossing Symmetry

We have studied the neutrino–electron processes in a matter with an external magnetic field of an arbitrary strength. Invariant squares of S-matrix elements, which have been obtained for such reactions using the technique based on the density matrix of a particle propagating in an external magnetic field, are valid in an arbitrary frame of reference moving along the magnetic field lines. The transition probabilities obtained can easily be generalized to the processes of interaction of a neutrino with other charged leptons and protons. The probabilities of the processes have been integrated over the transverse momenta of charged particles for the rates of neutrino–electron reactions as well as the energy and momentum transferred in them from the medium to neutrinos. The expressions obtained are written in the unified form for all neutrino–electron processes.