LMA and sterile neutrinos: a case for resonance spin flavour precession?

Abstract

Open questions remain after the confirmation of LMA as the dominant solution to the solar neutrino deficit. These are the apparent time modulation of the solar neutrino event rates in the Homestake, Gallium and SuperKamiokande experiments, possibly related to solar magnetic activity, the discrepancy between the event rate in the Homestake experiment and its theoretical prediction and the absence of the electron spectrum upturn in SuperKamiokande at energies below 6-8 MeV. We search for a possible understanding of these questions in the context of resonant spin flavour precession to sterile neutrinos, assuming a class of magnetic field profiles anchored in the upper radiation/lower convection zone. We consider the simplest such model beyond the standard 2$\nu$ flavour LMA one, with one single magnetic moment transition between active and sterile state and vanishing vacuum mixing. The preferred mass square difference is $\Delta m_{10}^2=O(10^{-8}e{V}^2)$. The Ga rate appears to be the most sensitive of all to solar activity. It is also found that a field profile extending within a longer region in the radial direction is favoured over another with a shorter span, and leads to a stronger suppression than in the LMA case of the intermediate energy neutrinos and some of the ${}^{8}B$ ones.

References updated. Final version to be published in JHEP

References in corpus (8)

• Measurement of the Total Active 8B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity
• Non-adiabatic Level Crossing in Resonant Neutrino Oscillations
• What do we (not) know theoretically about solar neutrino fluxes?
• Status of three-neutrino oscillations after the SNO-salt data
• A High Sensitivity Search for ${\bar{\nu }}_e$'s from the Sun and Other Sources at KamLAND
• Constraints on neutrino oscillation parameters from the SNO salt phase data
• Solar neutrinos: the SNO salt phase results and physics of conversion
• Constraints on Neutrino Parameters from Neutral-Current Solar Neutrino Measurements

Cited by in corpus (16)

• Power-Spectrum Analyses of Super-Kamiokande Solar Neutrino Data: Variability and its Implications for Solar Physics and Neutrino Physics
• Evidence for Solar Neutrino Flux Variability and its Implications
• Comparative analysis of Gallex and GNO solar neutrino data
• Low Energy Solar Neutrinos and Spin Flavour Precession
• Combined analysis of solar neutrino and solar irradiance data: further evidence for variability of the solar neutrino flux and its implications concerning the solar core
• Relaxed constraints on neutrino oscillation parameters
• Evidence for R-Mode Oscillations in Super-Kamiokande Solar Neutrino Data
• Light sterile neutrinos, spin flavour precession and the solar neutrino experiments
• Analysis of bimodality in histograms formed from GALLEX and GNO solar neutrino data
• SNO+: predictions from standard solar models and spin flavour precession
• Comparative Analysis of Super-Kamiokande and SNO Solar-Neutrino Data and the Photospheric Magnetic Field
• ${}^{7}Be$ Neutrino Signal Variation in KamLAND
• Neutrino spin-flavor oscillations in rapidly varying external fields
• Two Gallium data sets, spin flavour precession and KamLAND
• Gallium data variability and KamLAND
• Spectral Distortions at Super-Kamiokande