Electron energy spectra, fluxes, and day-night asymmetries of {sup 8}B solar neutrinos from measurements with NaCl dissolved in the heavy-water detector at the Sudbury Neutrino Observatory

Journal Article · Tue Nov 01 00:00:00 EST 2005 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PhysRevC.72.055502· OSTI ID:20699143

Aharmim, B; Fleurot, F; Hallman, E D; Krueger, A; Luoma, S; Schwendener, M H; Tafirout,; Virtue, C J.R. ^[1]; Ahmed, S N; Chen, M; Duncan, F A; Earle, E D; Evans, H C; Ewan, G T; Fulsom, B G; Graham, K; Hallin, A L; Handler, W B; Harvey, P J; Howard, C ^[2]

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1. Department of Physics and Astronomy, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada)
2. Department of Physics, Queen's University, Kingston, Ontario, K7L 3N6 (Canada); and others

Results are reported from the complete salt phase of the Sudbury Neutrino Observatory experiment in which NaCl was dissolved in the {sup 2}H{sub 2}O (''D{sub 2}O'') target. The addition of salt enhanced the signal from neutron capture as compared to the pure D{sub 2}O detector. By making a statistical separation of charged-current events from other types based on event-isotropy criteria, the effective electron recoil energy spectrum has been extracted. 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 is found to be 4.94{sub -0.21}{sup +0.21}(stat){sub -0.34}{sup +0.38}(syst) and the integral flux of electron neutrinos for an undistorted {sup 8}B spectrum is 1.68{sub -0.06}{sup +0.06}(stat){sub -0.09}{sup +0.08}(syst); the signal from ({nu}{sub x},e) elastic scattering is equivalent to an electron-neutrino flux of 2.35{sub -0.22}{sup +0.22}(stat){sub -0.15}{sup +0.15}(syst). These results are consistent with those expected for neutrino oscillations with the so-called large mixing angle parameters and also with an undistorted spectrum. A search for matter-enhancement effects in the Earth through a possible day-night asymmetry in the charged-current integral rate is consistent with no asymmetry. Including results from other experiments, the best-fit values for two-neutrino mixing parameters are {delta}m{sup 2}=(8.0{sub -0.4}{sup +0.6})x10{sup -5} eV{sup 2} and {theta}=33.9{sub -2.2}{sup +2.4} degrees.

• OSTI ID: 20699143
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 72, Issue 5; Other Information: DOI: 10.1103/PhysRevC.72.055502; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA). SNO Collaboration; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ASYMMETRY
BORON 8
CAPTURE
CHARGED CURRENTS
COSMIC NEUTRINOS
ELASTIC SCATTERING
ELECTRON NEUTRINOS
ELECTRONS
ENERGY SPECTRA
HEAVY WATER
ISOTROPY
NEUTRINO DETECTION
NEUTRINO OSCILLATION
NEUTRINO-ELECTRON INTERACTIONS
NEUTRON REACTIONS
NUCLEAR DECAY
SODIUM CHLORIDES
SOLAR NEUTRINOS
SUDBURY NEUTRINO OBSERVATORY
WEINBERG ANGLE