Low-energy-threshold analysis of the Phase I and Phase II data sets of the Sudbury Neutrino Observatory
- Department of Physics and Astronomy, Laurentian University, Sudbury, Ontario P3E 2C6 (Canada)
- Department of Physics, Queen's University, Kingston, Ontario K7L 3N6 (Canada)
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{sub eff}=3.5 MeV, the lowest analysis threshold yet achieved with water Cherenkov detector data. In units of 10{sup 6} cm{sup -2} s{sup -1}, the total flux of active-flavor neutrinos from {sup 8}B decay in the Sun measured using the neutral current (NC) reaction of neutrinos on deuterons, with no constraint on the {sup 8}B neutrino energy spectrum, is found to be PHI{sub NC}=5.140{sub -0.158}{sup +0.160}(stat){sub -0.117}{sup +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 {sup 8}B neutrino flux and the energy-dependent nu{sub e} survival probability provides a measure of the total {sup 8}B neutrino flux PHI{sub {sup 8}{sub B}}=5.046{sub -0.152}{sup +0.159}(stat){sub -0.123}{sup +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{sub 12}=34.06{sub -0.84}{sup +1.16} degrees and DELTAm{sub 21}{sup 2}=7.59{sub -0.21}{sup +0.20}x10{sup -5} eV{sup 2}. The global value of PHI{sup 8}{sub B} is extracted to a precision of {sub -2.95}{sup +2.38}%. In a three-flavor analysis the best fit value of sin{sup 2}theta{sub 13} is 2.00{sub -1.63}{sup +2.09}x10{sup -2}. This implies an upper bound of sin{sup 2}theta{sub 13}<0.057 (95% C.L.).
- OSTI ID:
- 21389069
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 81, Issue 5; Other Information: DOI: 10.1103/PhysRevC.81.055504; (c) 2010 The American Physical Society; ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BORON 8
CHARGED CURRENTS
CHERENKOV COUNTERS
DECAY
DEUTERONS
ELASTIC SCATTERING
ELECTRON NEUTRINOS
ELECTRONS
ENERGY DEPENDENCE
ENERGY SPECTRA
FLAVOR MODEL
KINETIC ENERGY
MEV RANGE 01-10
MIXING
NEUTRAL CURRENTS
RECOILS
SUDBURY NEUTRINO OBSERVATORY
SULFUR IONS
WATER
ALGEBRAIC CURRENTS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BORON ISOTOPES
CHARGED PARTICLES
COMPOSITE MODELS
CURRENTS
ELEMENTARY PARTICLES
ENERGY
ENERGY RANGE
FERMIONS
HYDROGEN COMPOUNDS
IONS
ISOTOPES
LEPTONS
LIGHT NUCLEI
MASSLESS PARTICLES
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MEV RANGE
MILLISECONDS LIVING RADIOISOTOPES
NEUTRINOS
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
PARTICLE MODELS
QUARK MODEL
RADIATION DETECTORS
RADIOISOTOPES
SCATTERING
SPECTRA