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Low-energy-threshold analysis of the Phase I and Phase II data sets of the Sudbury Neutrino Observatory

Research output: Contribution to journalJournal articlepeer-review

  • B. Aharmim
  • S. N. Ahmed
  • A. E. Anthony
  • N. Barros
  • E. W. Beier
  • A. Bellerive
  • B. Beltran
  • M. Bergevin
  • S. D. Biller
  • K. Boudjemline
  • M. G. Boulay
  • T. H. Burritt
  • B. Cai
  • Y. D. Chan
  • D. Chauhan
  • M. Chen
  • B. T. Cleveland
  • G. A. Cox
  • X. Dai
  • H. Deng
  • J. Detwiler
  • M. DiMarco
  • P. J. Doe
  • G. Doucas
  • P-L. Drouin
  • C. A. Duba
  • F. A. Duncan
  • M. Dunford
  • E. D. Earle
  • S. R. Elliott
  • H. C. Evans
  • G. T. Ewan
  • J. Farine
  • H. Fergani
  • F. Fleurot
  • R. J. Ford
  • J. A. Formaggio
  • N. Gagnon
  • J. Tm Goon
  • K. Graham
  • E. Guillian
  • S. Habib
  • R. L. Hahn
  • A. L. Hallin
  • E. D. Hallman
  • P. J. Harvey
  • R. Hazama
  • W. J. Heintzelman
  • Helen O'Keeffe
  • SNO Collaboration
  • Laura Kormos
Article number055504
<mark>Journal publication date</mark>05/2010
<mark>Journal</mark>Physical Review C
Issue number5
Number of pages49
Pages (from-to)-
Publication StatusPublished
<mark>Original language</mark>English


Results are reported from a joint analysis of Phase I and Phase II data from the Sudbury Neutrino Observatory. The effective electron kinetic energy threshold used is T-eff = 3.5MeV, the lowest analysis threshold yet achieved with water Cherenkov detector data. In units of 106 cm(-2) s(-1), the total flux of active-flavor neutrinos from B-8 decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the B-8 neutrino energy spectrum, is found to be Phi(NC) = 5.140(-0.158)(+0.160)(stat)(-0.117)(+0.132)(syst). These uncertainties are more than a factor of 2 smaller than previously published results. Also presented are the spectra of recoil electrons from the charged current reaction of neutrinos on deuterons and the elastic scattering of electrons. A fit to the Sudbury Neutrino Observatory data in which the free parameters directly describe the total B-8 neutrino flux and the energy-dependent nu(e) survival probability provides a measure of the total B-8 neutrino flux Phi(8B) = 5.046(-0.152)(+0.159)(stat)(-0.123)(+0.107)(syst). Combining these new results with results of all other solar experiments and the KamLAND reactor experiment yields best- fit values of the mixing parameters of theta(12) = 34.06(-0.84)(+1.16) degrees and Delta m(21)(2) = 7.59(-0.21)(+0.20) x 10(-5) eV(2). The global value of Phi(8B) is extracted to a precision of (+2.38)(-2.95)%. In a three-flavor analysis the best fit value of sin(2) theta(13) is 2.00(-1.63)(+2.09) x 10(-2). This implies an upper bound of sin(2) theta(13) < 0.057 (95% C.L.).

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© 2010 The American Physical Society