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Title: Search for periodicities in the experimental solar neutrino data: A wavelet approach

Abstract

The time series of the {sup 8}B solar neutrino measurements released by the Super- Kamiokande and SNO Collaborations have been recently investigated by several groups for possible modulation signatures through standard Fourier-based techniques. In this work we present an alternative analysis of the same data sets based on the wavelet approach, whose key advantage with respect to the traditional methodologies is the ability to capture and follow the time evolution of transient modulation features as well. Moreover, we show the results of the wavelet analysis applied to the mean solar magnetic field and flare index data recorded in the same data-taking period of the two experiments, with the goal of carrying out a direct check of the concurrent presence (if any) of evidence for corresponding time variations in the solar data and in the solar neutrino series. The main outcomes of this investigation are, on one hand, the clear identification of the expected annual modulation variation due to the eccentricity of the Earth's orbit, and on the other, the demonstration that no further reliable time variation signals can be unraveled, within the current experimental sensitivity, in the measured solar neutrino flux.

Authors:
;  [1];  [2]
  1. Istituto Nazionale di Fisica Nucleare, Via Celoria 16, 20133 Milan (Italy)
  2. (Italy)
Publication Date:
OSTI Identifier:
21020248
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 7; Other Information: DOI: 10.1103/PhysRevD.75.073011; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; BORON 8; CAPTURE; MAGNETIC FIELDS; MODULATION; NEUTRINO DETECTION; NEUTRINO REACTIONS; PERIODICITY; SENSITIVITY; SOLAR NEUTRINOS

Citation Formats

Ranucci, Gioacchino, Sello, Stefano, and Mathematical and Physical Models-Enel Research, Via Andrea Pisano 120, 56122 Pisa. Search for periodicities in the experimental solar neutrino data: A wavelet approach. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.073011.
Ranucci, Gioacchino, Sello, Stefano, & Mathematical and Physical Models-Enel Research, Via Andrea Pisano 120, 56122 Pisa. Search for periodicities in the experimental solar neutrino data: A wavelet approach. United States. doi:10.1103/PHYSREVD.75.073011.
Ranucci, Gioacchino, Sello, Stefano, and Mathematical and Physical Models-Enel Research, Via Andrea Pisano 120, 56122 Pisa. Sun . "Search for periodicities in the experimental solar neutrino data: A wavelet approach". United States. doi:10.1103/PHYSREVD.75.073011.
@article{osti_21020248,
title = {Search for periodicities in the experimental solar neutrino data: A wavelet approach},
author = {Ranucci, Gioacchino and Sello, Stefano and Mathematical and Physical Models-Enel Research, Via Andrea Pisano 120, 56122 Pisa},
abstractNote = {The time series of the {sup 8}B solar neutrino measurements released by the Super- Kamiokande and SNO Collaborations have been recently investigated by several groups for possible modulation signatures through standard Fourier-based techniques. In this work we present an alternative analysis of the same data sets based on the wavelet approach, whose key advantage with respect to the traditional methodologies is the ability to capture and follow the time evolution of transient modulation features as well. Moreover, we show the results of the wavelet analysis applied to the mean solar magnetic field and flare index data recorded in the same data-taking period of the two experiments, with the goal of carrying out a direct check of the concurrent presence (if any) of evidence for corresponding time variations in the solar data and in the solar neutrino series. The main outcomes of this investigation are, on one hand, the clear identification of the expected annual modulation variation due to the eccentricity of the Earth's orbit, and on the other, the demonstration that no further reliable time variation signals can be unraveled, within the current experimental sensitivity, in the measured solar neutrino flux.},
doi = {10.1103/PHYSREVD.75.073011},
journal = {Physical Review. D, Particles Fields},
number = 7,
volume = 75,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}
  • No abstract prepared.
  • A search has been made for sinusoidal periodic variations in the {sup 8}B solar neutrino flux using data collected by the Sudbury Neutrino Observatory over a 4-year time interval. The variation at a period of 1 yr is consistent with modulation of the {sup 8}B neutrino flux by the Earth's orbital eccentricity. No significant sinusoidal periodicities are found with periods between 1 d and 10 years with either an unbinned maximum likelihood analysis or a Lomb-Scargle periodogram analysis. The data are inconsistent with the hypothesis that the results of the recent analysis by Sturrock et al., based on elastic scatteringmore » events in Super-Kamiokande, can be attributed to a 7% sinusoidal modulation of the total {sup 8}B neutrino flux.« less
  • Cited by 12
  • In this work a detailed spectral analysis for the periodicity search of the time series of the {sup 8}B solar neutrino flux released by the SNO Collaboration is presented. The data have been publicly released with truncation of the event times to the unit of day (1 day binning); they are thus suited to undergo the traditional Lomb-Scargle analysis for periodicity investigation, as well as an extension of such a method based on a likelihood approach. The results of the analysis presented here confirm the absence of modulation signatures in the SNO data. For completeness, a more refined ''1 daymore » binned'' likelihood is also illustrated, which approximates the unbinned likelihood methodology, based upon the availability of the full time information, adopted by the SNO collaboration. Finally, this work is completed with two different joint analyses of the SNO and Super-Kamiokande data, respectively, over the common and the entire data taking periods. While both analyses reinforce the case of the constancy of the neutrino flux, the latter in addition provides evidence of the detection at the 99.7% confidence level of the annual modulation spectral line due to the Earth's orbit eccentricity around the Sun.« less
  • The multifractal nature of solar photospheric magnetic structures is studied using the two-dimensional wavelet transform modulus maxima (WTMM) method. This relies on computing partition functions from the wavelet transform skeleton defined by the WTMM method. This skeleton provides an adaptive space-scale partition of the fractal distribution under study, from which one can extract the multifractal singularity spectrum. We describe the implementation of a multiscale image processing segmentation procedure based on the partitioning of the WT skeleton, which allows the disentangling of the information concerning the multifractal properties of active regions from the surrounding quiet-Sun field. The quiet Sun exhibits anmore » average Hoelder exponent {approx}-0.75, with observed multifractal properties due to the supergranular structure. On the other hand, active region multifractal spectra exhibit an average Hoelder exponent {approx}0.38, similar to those found when studying experimental data from turbulent flows.« less