Determination of Neutrino mixing parameters after SNO oscillation evidence
نویسندگان
چکیده
An updated analysis of all available neutrino oscillation evidence in Solar experiments (SK day and night spectra, global rates from Homestake, SAGE and GALLEX) including the latest SNOCC and NC data is presented. Assuming that the shape of the SNO CC energy spectrum is undistorted and using the information provided by SNO we obtain, for the fraction of electron neutrinos remaining in the solar beam at energies >∼ 5 MeV: φCC/φNC = 0.34 +0.05 −0.04, which is nominally ∼ 30σ away from the standard value (∼ 1.8 ± 0.1). The fraction of oscillating neutrinos which into active ones is computed to be: (ΦNC − ΦCC)/(ΦSSM − ΦCC) = 0.92 +0.39 −0.20 nearly 5σ deviations from the pure sterile oscillation case. The data is still compatible with an important fraction of sterile component in the solar beam (up to 20% of the total). In the framework of two active neutrino oscillations we determine individual neutrino mixing parameters and their errors in the region of no spectrum distortion (∆〈Te〉 < 1%), we obtain ∆m = 4.5 −1.4 × 10 eV, tan θ = 0.40 −0.08. This is in agreement with the best chi solution in the LMA region. PACS: ⋆ email: [email protected], [email protected], [email protected], [email protected]
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