2000/02/20 by André de Gouvêa, Andre de Gouvea, Alexander Friedland +1 · 10 citations
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Neutrino Physics Research #Particle physics theoretical and experimental studies #astro-ph #hep-ex #hep-ph #nucl-ex #nucl-th
paper · pdf · doi:10.1016/s0370-2693(00)00989-8
published as Phys.Lett.B490:125-130,2000 · 4 pages, 3 figures, uses psfig. Fixed typos in Eq. (3). An imprecise comment in the footnote removed
arxiv created 2000/02/20 · openalex publication_date 2000/09/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Results of neutrino oscillation experiments have always been presented on the (sin2 2theta, Delta m2) parameter space for the case of two-flavor oscillations. We point out, however, that this parameterization misses the half of the parameter space pi/4 < theta <= pi/2 (``the dark side''), which is physically inequivalent to the region 0 <= theta <= pi/4 (``the light side'') in the presence of matter effects. The MSW solutions to the solar neutrino problem can extend to the dark side, especially if we take the conservative attitude to allow higher confidence levels, ignore some of the experimental results in the fits, or relax theoretical predictions. Furthermore even the so-called ``vacuum oscillation'' solution distinguishes the dark and the light sides. We urge experimental collaborations to present their results on the entire parameter space.