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ISDCCAPCDCI
Data Centre for Astrophysics
Astronomy Department of the University of Geneva
ISDC Seminar

Friday, June 29, 2001 at 11:00

J. Farine
Carleton University, Canada

Measurement of charged current interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory

Abstract. Solar neutrinos from the decay of 8B have been detected at the Sudbury Neutrino Observatory (SNO) via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons.
The CC reaction is sensitive exclusively to nue's, while the ES reaction also has a small sensitivity to numu's and nutau's. The flux of nue's from 8B decay measured by the CC reaction rate is
phiCC(nue) = 1.75+-0.07(stat.)+0.12-0.11(syt.)+-0.05(theor) x 106 cm-2s-1.
Assuming no flavor transformation, the flux inferred from the ES reaction rate is
phiES(nux) = 2.39+-0.34(stat.)+0.16-0.14(sys.) x 106 cm-2s-1.

Comparison of phiCC(nue) to the Super-Kamiokande Collaboration's precision value of phiES(nux) yields a 3.3 sigma difference, providing evidence that there is a non-electron flavor active neutrino component in the solar flux. The total flux of active 8B neutrinos is thus determined to be 5.44+-0.99 x 106 cm-2s-1, in close agreement with the predictions of solar models.

The data selection and analysis procedures leading to the first SNO results will be presented. The future plans will then be outlined.

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