113 research outputs found
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
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
Effects of non-standard neutrino interactions on MSW-LMA solution to the solar neutrino problem
We show that the non-standard neutrino interactions can play a role as
sub-leading effect on the solar neutrino oscillations. We observe that very
small flavor universality violations of order of 0.1-0.2 G_F is sufficient to
induce two phenomena: suppression of the eletronic neutrino earth regeneration
and a shift of the resonance layer in the sun. We obtain these phenomena even
in the absence of any flavor changing interactions. We discuss their
consequences and confront with a global analysis of solar+KamLAND results. We
conclude that a new compatibility region in the Delta m^2 x tan^2\theta, which
we call very low Large Mixing Angle region, is found for Delta m^2 ~ 1e-5 eV^2
and tan^2\theta= 0.45.Comment: references added, small changes in text, some changes in predictions
of KamLAND future sensitivity to NSNI parameter
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
MHD solar fluctuations and solar neutrinos
We analyze how solar neutrino experiments could detect time fluctuations of the solar neutrino flux due to magnetohydrodynamic (MHD) perturbations of the solar plasma. We state that if such time fluctuations are detected, this would provide a unique signature of the Resonant Spin-Flavor Precession (RSFP) mechanism as a solution to the Solar Neutrino Problem.707774Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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
Recontextualizing bodily ornaments from north-central Venezuela (AD 900-1500): the Alfredo Jahn collection at the Ethnologisches Museum Berlin
Large collections of beads,
pendants and other bodily ornaments have been recovered from pre-Colonial
contexts on the shores of the Lake Valencia in north-central Venezuela. Most
excavations took place in the early and mid-part of the 20th century, but the ornaments
have not been thoroughly studied to date. These artefacts were produced by the
bearers of the Valencioid culture (AD 900-1500) and are currently held in
several public and private collections dispersed throughout the world. This
paper aims to recontextualize shell, lithic, and clay ornaments from the Alfredo
Jahn collection, housed in the Ethnologisches Museum in Berlin. Production and
use wear traces were investigated through microwear analysis and were combined
with data concerning raw material acquisition strategies and depositional
contexts. By combining these results with new, unpublished data provided by
Jahn’s excavation report from 1901 and with up-to-date Valencioid archaeology,
we were able to recontextualize an indigenous tradition that encompassed ways
of producing, decorating, and dealing with bodily ornaments.Material Culture StudiesArchaeology of the America
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 -analysis ranges between and . 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
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
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
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