Current Status of the Resonant Spin-Flavor Precession Solution to the Solar Neutrino Problem

We discuss the current status of the resonant spin-flavor precession (RSFP) solution to the solar neutrino problem. We perform a fit to all the latest solar neutrino data for various assumed magnetic field profiles in the sun. We show that the RSFP can account for all the solar neutrino experiments, giving as good fit as other alternative solutions such as MSW or Just so, and therefore can be a viable solution to the solar neutrino problemComment: RevTex file, 9 pages, 12 postscript figures, Some errors are corrected, some changes in results but no change in conclusions, version to appear in Astroparticle Physic

Ultra High Energy Tau Neutrinos and Fluorescence Detectors: A Phenomenological Approach

We investigate the possibility of detecting ultra-high energy cosmic tau-neutrinos by means of a process involving a double extensive air shower, the so-called Double-Bang Phenomenon. In this process a primary tau-neutrino interacts with an atmospheric quark creating a hadronic extensive air shower that contains a tau which subsequently decays creating a second extensive air shower. The number of these events strongly depends on the cross section and on the flux of ultra-high energy tau-neutrinos arriving at the Earth's atmosphere. We estimate the potential of optical detectors to observe Double-Bang events induced by tau-neutrinos with energies of about 1 EeV whose detection may confirm the maximal mixing observed in the atmospheric neutrinos also for ultra-high energy neutrinos, and give information on the neutrino flux and cross-section. For neutrino-nucleon Standard Model extrapolated cross-section and thick source model of flux (MPR), we estimate an event rate of 0.48/yr for an observatory with two fluorescence detectors with 90% efficiency in the neutrino energy range 0.5 < E_nu < 5 EeV.Comment: 17 pages, 6 eps figures, revtex 4, new calculation for the interaction probability end efficienc

Status of a hybrid three-neutrino interpretation of neutrino data

We reanalyze the non-standard interaction (NSI) solutions to the solar neutrino problem in the light of the latest solar, atmospheric and reactor neutrino data. We show that such solutions, although preferred by the solar data and consistent with the oscillation description of the atmospheric neutrino data, are ruled out by the first results of the KamLAND reactor experiment, at more than 3_sigma.Comment: 19 pages, LaTeX file using Elsart, 2 tables and 4 figures included. This version updates the one published in Nucl.Phys.B629:479-490,2002 by including the new KamLAND dat

Twisting Magnetic Field And Multiple Resonance Mechanism In The Solar Neutrino Problem

The magnetic moment solution to the solar neutrino problem is investigated in the context of a solar magnetic field with varying phase velocity on the transverse plane. This phase velocity is assumed to successively take values which are approximately proportional to the solar density, giving rise to the appearance of many resonances along the neutrino trajectory. We obtain a magnetic moment necessary for a neutrino reduction compatible with the experimental situation in the range (6-7)×10-13μB, an improvement by a factor of 4-6 relative to the one resonance case under the same field conditions. © 1993.31701/02/15125129Lim, Marciano, (1988) Phys. Rev. D, 37, p. 1368Akhmedov, (1988) Phys. Lett. B, 213, p. 64Balantekin, Hatchell, Loreti, (1990) Phys. Rev. D, 41, p. 3583Pulido, (1992) Phys. Rep., 211, p. 167IFM preprint 19/92, to be publishedBahcall, Ulrich, (1988) Rev. Mod. Phys., 60, p. 297Bahcall, Pinsonneault, (1992) Rev. Mod. Phys., 64, p. 885Davis, (1990) Proc. XXI Cosmic ray Conf., 7, p. 155. , Adelaide, AustraliaAbazov, (1991) Phys. Rev. Lett, 67, p. 3332Hirata, (1991) Phys. Rev. D, 44, p. 2241Anselman, (1991) Phys. Lett. B, 281, p. 376Anselman, (1991) Phys. Lett. B, 281, p. 390Voloshin, Vysotskii, Okun, (1986) Sov. J. Nucl. Phys., 44, p. 440Voloshin, Vysotskii, (1986) Sov. J. Nucl. Phys., 44, p. 544Fujikawa, Shrock, (1980) Phys. Rev. Lett., 45, p. 963Marciano, Parsa, Electroweak Tests of the Standard Model (1986) Annual Review of Nuclear and Particle Science, 36, p. 171Krakauer, (1990) Phys. Lett. B, 252, p. 177. , see alsoWolfenstein, (1978) Phys. Rev. D, 17, p. 2369Wolfenstein, Neutrino oscillations and stellar collapse (1979) Physical Review D, 20, p. 2364Mikheyev, Smirnov, (1985) Sov. J. Nucl. Phys., 42, p. 913Rosen, Gelb, (1986) Phys. Rev. D, 34, p. 969Wudka, Vidal, (1988) UCD-88-40, , University of California preprintAneziris, Schechter, NEUTRINO “SPIN ROTATION” IN A TWISTING MAGNETIC FIELD (1991) International Journal of Modern Physics A, 6, p. 2375Vidal, Wudka, (1990) Phys. Lett. B, 249, p. 473Smirnov, (1991) Phys. Lett. B, 260, p. 161Toshev, (1991) Phys. Lett. B, 271, p. 179Akhmedov, Bychuk, (1989) Sov. Phys. JETP, 68, p. 250IFM preprint 19/92, to be publishedBabu, Mohapatra, Rothstein, (1991) Phys. Rev. D, 44, p. 2265see also E.Kh. Akhmedov, A. Lanza and S.T. Petcov, SISSA preprint 172/92/EP (1992)Mourão, Pulido, Ralston, The neutrino electromagnetic moments and charge radius confront Kamiokande II and Homestake experimental results (1992) Physics Letters B, 285, p. 36

Atmospheric Neutrino Oscillations and New Physics

We study the robustness of the determination of the neutrino masses and mixing from the analysis of atmospheric and K2K data under the presence of different forms of phenomenologically allowed new physics in the nu_mu--nu_tau sector. We focus on vector and tensor-like new physics interactions which allow us to treat, in a model independent way, effects due to the violation of the equivalence principle, violations of the Lorentz invariance both CPT conserving and CPT violating, non-universal couplings to a torsion field and non-standard neutrino interactions with matter. We perform a global analysis of the full atmospheric data from SKI together with long baseline K2K data in the presence of nu_mu -> nu_tau transitions driven by neutrino masses and mixing together with sub-dominant effects due to these forms of new physics. We show that within the present degree of experimental precision, the extracted values of masses and mixing are robust under those effects and we derive the upper bounds on the possible strength of these new interactions in the nu_mu--nu_tau sector.Comment: 22 pages, LaTeX file using RevTEX4, 5 figures and 4 tables include

Status of a Supersymmetric Flavour Violating Solution to the Solar Neutrino Puzzle with Three Generations

We present a general study of a three neutrino flavour transition model based on the supersymmetric interactions which violate R-parity. These interactions induce flavour violating scattering reactions between solar matter and neutrinos. The model does not contain any vacuum mass or mixing angle for the first generation neutrino. Instead, the effective mixing in the first generation is induced via the new interactions. The model provides a natural interpretation of the atmospheric neutrino anomaly, and is consistent with reactor experiments. We determine all R-parity violating couplings which can contribute to the effective neutrino oscillations, and summarize the present laboratory bounds. Independent of the specific nature of the (supersymmetric) flavour violating model, the experimental data on the solar neutrino rates and the recoil electron energy spectrum are inconsistent with the theoretical predictions. The confidence level of the $\chi^2$-analysis ranges between $\sim 10^{-4}$ and $\sim 10^{-3}$. The incompatibility, is due to the new SNO results, and excludes the present model. We conclude that a non-vanishing vacuum mixing angle for the first generation neutrino is necessary in our model. We expect this also to apply to the solutions based on other flavour violating interactions having constraints of the same order of magnitude.Comment: 17 pages, Latex fil

Slow Solar Magnetosonic Waves And Time Variation In The Solar Neutrino Data

We analyze the perturbations of the solar magnetic field generated by general solar plasma displacements and investigate their consequences in the left-right conversion probability of neutrinos produced in the Sun. We solve the Hain-Lüst equation and the evolution equations of neutrinos interacting with the solar magnetic field through a nonvanishing neutrino magnetic moment to conclude that the appearance of slow magnetosonic waves (with a period around 100 days) simulate the time behavior of solar neutrino data. © 1995.3574602607Davis, (1990) Proc. of the XXI Int. Cosmic Ray Conference, 7, p. 155. , Adelaide, AustraliaHirata, (1991) Phys. Rev. D, 44, p. 2241Anselmann, (1992) Phys. Lett. B, 285, p. 390Abazov, (1991) Phys. Rev. Lett., 67, p. 3332Voloshin, Vysotsky, Okun, (1986) Yad. Fiz., 44, p. 677Voloshin, Vysotsky, Okun, (1986) Sov. J. Nucl. Phys., 44, p. 440Mikheyev, Smirnov, (1986) Nuovo Cimento C, 9, p. 17Mikheyev, Smirnov, (1985) Yad. Fiz., 42Mikheyev, Smirnov, (1985) Sov. J. Nucl. Phys., 42, p. 913Wolfenstein, (1978) Phys. Rev. D, 17, p. 2369Wolfenstein, (1979) Phys. Rev. D, 20, p. 2634Bahcall, Ulrich, Solar models, neutrino experiments, and helioseismology (1988) Reviews of Modern Physics, 60, p. 298Gloedbloed, Sakanaka, New approach to magnetohydrodynamic stability: I. A practical stability concept (1974) Physics of Fluids, 17, p. 908Bernstein, Frieman, Kruskal, Kulsrud, (1958) Proc. Roy. Soc. A, 224, p. 1Hain, Lüst, (1958) Z. Naturforsch., 13 a, p. 936Akhmedov, Bychuk, (1989) Sov. Phys. JETP, 68, p. 250Smirnov, (1991) Phys. Lett. B, 260, p. 161Future Solar Neutrino Experiments (1995) Nuclear Physics B - Proceedings Supplements, 38, pp. 90-95Tatsuka, Superkamiokande (1990) ICCR-Report 227-90-20Chen, (1985) Phys. Rev. Lett., 55, p. 153

On the massless "just-so" solution to the solar neutrino problem

We study the effect of the non-resonant, vacuum oscillation-like neutrino flavor conversion induced by non-standard flavor changing and non-universal flavor diagonal neutrino interactions with electrons in the sun. We have found an acceptable fit for the combined analysis for the solar experiments total rates, the Super-Kamiokande (SK) energy spectrum and zenith angle dependence. Phenomenological constraints on non-standard flavor changing and non-universal flavor diagonal neutrino interactions are considered.Comment: 4 pages, Latex, uses eps

Effects of new physics in neutrino oscillations in matter

A new flavor changing electron neutrino interaction with matter would always dominate the nu_e oscillation probability at sufficiently high neutrino energies. Being suppressed by theta_{13}, the energy scale at which the new effect starts to be relevant may be within the reach of realistic experiments, where the peculiar dependence of the signal with energy could give rise to a clear signature in the nu_e --> nu_tau channel. The latter could be observed by means of a coarse large magnetized detector by exploiting tau --> mu decays. We discuss the possibility of identifying or constraining such effects with a high energy neutrino factory. We also comment on the model independent limits on them.Comment: 11 pages, 5 figure

Can lepton flavor violating interactions explain the LSND results?

If the atmospheric and the solar neutrino problem are both explained by neutrino oscillations, and if there are only three light neutrinos, then all mass-squared differences between the neutrinos are known. In such a case, existing terrestrial neutrino oscillation experiments cannot be significantly affected by neutrino oscillations, but, in principle there could be an anomaly in the neutrino flux due to new neutrino interactions. We discuss how a non-standard muon decay $\mu^+ \to e^+ \bar\nu_e \nu_\ell$ would modify the neutrino production processes of these experiments. Since $SU(2)_L$ violation is small for New Physics above the weak scale one can use related flavor-violating charged lepton processes to constrain these decays in a model independent way. We show that the upper bounds on $\mu \to 3e$, muonium-antimuonium conversion and $\tau \to \mu e e$ rule out any observable effect for the present experiments due to $\mu^+ \to e^+ \bar\nu_e \nu_\ell$ for $\ell=e,\mu,\tau$, respectively. Applying similar arguments to flavor-changing semi-leptonic reactions we exclude the possibility that the "oscillation signals" observed at LSND are due to flavor-changing interactions that conserve total lepton number.Comment: 21 pages, 6 figures, Latex; minor correction