Solar neutrino flux measurements by the Soviet-American gallium experiment (SAGE) for half the 22-year solar cycle

University of Washington Seattle, Seattle, Washington, United States
Journal of Experimental and Theoretical Physics (Impact Factor: 0.93). 01/2002; 95(2):181-193. DOI: 10.1134/1.1506424

ABSTRACT We present measurements of the solar neutrino capture rate on metallic gallium in the Soviet-American gallium experiment (SAGE)
over a period of slightly more than half the 22-year solar cycle. A combined analysis of 92 runs over the twelve-year period
from January 1990 until December 2001 yields a capture rate of 70.8
(sys) SNU for solar neutrinos with energies above 0.233 MeV. This value is slightly more than half the rate predicted by
the standard solar model, 130 SNU. We present the results of new runs since April 1998 and analyze all runs combined by years,
months, and bimonthly periods beginning in 1990. A simple analysis of the SAGE results together with the results of other
solar neutrino experiments gives an estimate of (4.6±1.2)× 1010 neutrinos cm−2 s−1 for the flux of the electron pp neutrinos that reach the Earth without changing their flavor. The flux of the pp neutrinos produced in thermonuclear reactions in the Sun is estimated to be (7.6 ± 2.0) × 1010 neutrinos cm−2 s−1, in agreement with the value of (5.95±0.06)×1010 neutrinos cm−2 s−1 predicted by the standard solar model.

  • [Show abstract] [Hide abstract]
    ABSTRACT: We study the rare decays of charged π mesons, π + → e +e +μ − $ \overline v $ μ and π + → e +μ −e +ν e induced by a sterile neutrino N with a mass in the range m μ < m N < m π . The first process violates Lepton Number by two units and so occurs only if N is Majorana, while the second process conserves Lepton Number and occurs irrespective of the Majorana or Dirac character of N . We study a way to distinguish the Majorana vs. Dirac character of N in these processes using the muon spectrum. We also find that the branching ratios could be at the reach of high luminosity experiments like Project X at FNAL or any proposed neutrino (or muon) factories worldwide.
    Journal of High Energy Physics 06/2012; 2012(6). DOI:10.1007/JHEP06(2012)149 · 6.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A method has been developed for the extraction of single 71Ge atoms from the gallium target of a Ga-Ge neutrino detector. The key features of this chemical process stem from the extremely low content of the element to be extracted in the sample (n × 10−27 at %), the large sample weight (up to n × 103 kg), the limited time available for the extraction and measurement of the extracted atoms (≤20 h), and small permissible loss (≤0.1%) of the target material at high degrees of 71Ge extraction (≥90%). The method involves forced generation and maintenance of a disperse system of liquid gallium droplets with an oxide surface film in an acid-peroxide solution. The small droplet size ensures a rapid 71Ge transfer from the bulk target to a small amount of gallium oxide. The 71Ge passes from the oxide film to the solution, is concentrated, and converts to germane, which is delivered to a proportional counter. We have assessed the completeness of germanium extraction in relation to process conditions. The results, in particular the completeness of extraction, have been verified in experiments with Ga + Ge mixtures at germanium concentrations of 10−4 and 10−17 to 10−16 wt %. The adequacy of the approaches used to develop the technology of the Ga-Ge detector is supported by satisfactory agreement between the solar neutrino fluxes obtained with gallium and gallium-chloride detectors.
    Inorganic Materials 12/2011; 47(12). DOI:10.1134/S0020168511120077 · 0.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A framework based on an effective symmetry that is either G(224)= SU(2)_L x SU(2)_R xSU(4)^c or SO(10) has been proposed (a few years ago) that successfully describes the masses and mixings of all fermions including neutrinos, with seven predictions, in good accord with the data. Baryogenesis via leptogenesis is considered within this framework by allowing for natural phases (~ 1/20-1/2) in the entries of the Dirac and Majorana mass-matrices. It is shown that the framework leads quite naturally, for both thermal as well as non-thermal leptogenesis, to the desired magnitude for the baryon asymmetry. This result is obtained in full accord with the observed features of the atmospheric and solar neutrino oscillations, as well as with those of the quark and charged lepton masses and mixings, and the gravitino-constraint. Hereby one obtains a unified description of fermion masses, neutrino oscillations and baryogenesis (via leptogenesis) within a single predictive framework. Comment: Efficiency factor updated, some clarifications and new references added. 19 pages
    Physical Review D 09/2002; 68(7). DOI:10.1103/PhysRevD.68.072002 · 4.86 Impact Factor
Show more