Solar neutrinos before and after Neutrino 2004

Abstract

We compare, using a three neutrino analysis, the allowed neutrino oscillation parameters and solar neutrino fluxes determined by the experimental data available Before and After Neutrino 2004. New data available after Neutrino 2004 include refined KamLAND and gallium measurements. We use six different approaches to analyzing the KamLAND data. We present detailed results using all the available neutrino and anti-neutrino data for Δm212, tan2θ12, sin2θ 13, and sin2η (sterile fraction). Using the same complete data sets, we also present Before and After determinations of all the solar neutrino fluxes (which are treated as free parameters), an upper limit to the luminosity fraction associated with CNO neutrinos, and the predicted rate for a 7Be solar neutrino experiment. The 1σ (3σ) allowed range of Δm212 = 8.2-0.3+0.3(-0.8 +1.0) × 10-5 eV2 is decreased by a factor of 1.7 (5), but the allowed ranges of all other neutrino oscillation parameters and neutrino fluxes are not significantly changed. Maximal θ12 mixing is disfavored at 5.8σ and the bound on the mixing angle θ13 is slightly improved to sin2 θ13 < 0.048 at 3σ. The predicted rate in a 7Be neutrino-electron scattering experiment is 0.665 ± 0.015 (-0.040+0.045) of the rate implied by the BP04 solar model in the absence of neutrino oscillations. The corresponding predictions for p - p and pep experiments are, respectively, 0.707-0.013+0.011 (-0.039+0.041) and 0.644-0.013+0.011(-0.037+0.045). In order to clarify what measurements constrain which parameters best, we also analyze the solar neutrino data separately and the reactor anti-neutrino data separately, both Before and After Neutrino 2004. We derive upper limits to CPT violation in the weak sector by comparing reactor anti-neutrino oscillation parameters with neutrino oscillation parameters. We also show that the recent data disfavor at 91% CL a proposed non-standard interaction description of solar neutrino oscillations. We have verified that our results are insensitive (changes much less than 1σ) to which of six approaches we use in analyzing the KamLAND data, which of the published 8B neutrino energy spectra we adopt, and the precise value of the gallium solar neutrino event rate. © SISSA/ISAS 2004.