Confronting Spin Flavor Solutions of the Solar Neutrino Problem with current and future solar neutrino data

A global analysis of spin-flavour precession (SFP) solutions to the solar neutrino problem is given, taking into account the impact of the full set of latest solar neutrino data, including the recent SNO data and the 1496–day Super-Kamiokande data. These are characterized by three effective parameters: ∆m sol ≡ ∆m, the neutrino mixing angle θsol ≡ θ and the magnetic field parameter μB⊥. For the latter we adopt a self-consistent magneto-hydrodynamics field profile in the convective zone and identify an optimum B⊥ ∼ 80 KGauss strength for μ = 10 Bohr magneton. We find that no LOW-quasi-vacuum or vacuum solutions are present at 3 σ. In addition to the standard LMA oscillation solution, there are two SFP solutions, in the resonant (RSFP) and non-resonant (NRSFP) regimes. These two SFP solutions have goodness of fit 84 % (RSFP) and 83 % (NRSFP), slightly better than the LMA oscillation solution (78 %). We discuss the role of solar anti-neutrino searches in the fit and present a table of best-fit parameters and χ2min values. Should KamLAND confirm the LMA solution, the SFP solutions may at best be present at a sub-leading level, leading to a constraint on μB⊥. In the event LMA is not the solution realized in nature, then experiments such as Borexino can help distinguishing LMA from the NRSFP solution and the simplest RSFP solution with no mixing. In the appendix, we present an updated analysis combining the latest data from all solar neutrino experiments with the first results from KamLAND. We show that, although the SFP hypothesis still gives an excellent description of the solar data, it fails to account for the suppressed reactor neutrino flux detected at KamLAND. The inclusion of KamLAND excludes the SFP hypothesis at more than 3σ. PACS numbers: 14.60.Pq, 26.65.+t, 13.15.+g Electronic address: [email protected] Electronic address: [email protected] Electronic address: [email protected] Electronic address: [email protected], [email protected] Electronic address: [email protected]