Implications of combined solarneutrino observations and their theoretical uncertainties
Abstract
Constraints on the core temperature (T_{c}) of the Sun and on neutrinooscillation parameters are obtained from the existing solar neutrino data, including the recent GALLEX, SAGE, and Kamiokande III results. (1) A purely astrophysical solution to the solarneutrino problem is strongly disfavored by the data: the Homestake and Kamiokande data together are incompatible with any temperature in the Sun; the central values of both the SAGE and GALLEX results require a large reduction of T_{c} when they are fit to a cooler Sun. (2) Assuming the standard solar model (SSM) and matterenhanced neutrino oscillations, the MikheyevSmirnovWolfenstein (MSW) parameters are constrained to two small regions: nonadiabatic oscillations with Δm^{2}=(0.31.2)×10^{5} eV^{2}, sin^{2}2θ=(0.41.5)×10^{2}, or large mixingangle oscillations with Δm^{2}=(0.33)×10^{5} eV^{2}, sin^{2}2θ=0.60.9. The nonadiabatic solution gives a considerably better fit. For ν_{e} oscillations into sterile neutrinos, the allowed region (90% C.L.) is constrained to nonadiabatic oscillations. As long as the SSM is assumed, the neutrino mixing angles are at least four times larger, or considerably smaller, than the corresponding quark mixing angles. (3) Allowing both MSW oscillations and a nonstandard core temperature, (a) the experiments determine the core temperature at the 5% level, T_{c}=1.02^{+0.03}_{0.05} (90% C.L.) relative to the SSM, and (b) when T_{c} is used as a free parameter, the allowed MSW region is broadened: a 2% cooler Sun allows Δm^{2}, sin^{2}2θ implied by the supersymmetric SO(10) grand unified theory (GUT), while a 34% warmer Sun extends the allowed parameter space into values suggested by intermediatescale SO(10) GUT's, for which the ν_{τ} may be cosmologically relevant. Superstringinspired models are consistent with all solutions. (4) From the narrowed parameter space, we predict the neutrino spectral shape which should be observed in the Sudbury Neutrino Observatory (SNO). Expected rates for SNO, SuperKamiokande, and BOREXINO are also discussed. Throughout the calculation we use the BahcallPinsonneault SSM (1992) with helium diffusion, and include nuclear and astrophysical uncertainties in a simplified, but physically transparent way.
 Publication:

Physical Review D
 Pub Date:
 March 1993
 DOI:
 10.1103/PhysRevD.47.2220
 arXiv:
 arXiv:hepph/9207213
 Bibcode:
 1993PhRvD..47.2220B
 Keywords:

 96.60.Kx;
 14.60.Gh;
 High Energy Physics  Phenomenology;
 Astrophysics
 EPrint:
 20 pages, 19 figures (not included), Latex, UPR0516T