Solar Evidence for Neutrino Transition Magnetic Moments and Sterile Neutrinos – David Caldwell

Date: Fri. July 9th, 2004, 1:30 pm-2:30 pm
Location: Rockefeller 221

While KamLAND apparently rules out Resonant-Spin-Flavor-Precession (RSFP) as an explanation of the solar neutrino deficit, the solar neutrino fluxes in the Cl and Ga experiments appear to vary with solar rotation. Added to this evidence, summarized here, a power spectrum analysis of the Super-Kamiokande (SK) data reveals significant variation in the flux matching a dominant rotation rate observed in the solar magnetic field in the same time period. Four frequency peaks, all related to this rotation rate, can be explained quantitatively. A recent SK paper reported no time variation of the flux, but showed the same peaks with statistically insignificant sensitivity, resulting from an inappropriate analysis. This modulation would be small (7%) in the SK energy region for RSFP as a subdominant neutrino process in the convection zone. The data display effects that correspond to solar-cycle changes in the magnetic field, typical of the convection zone. This subdominant process requires new physics: a large neutrino transition magnetic moment and a light sterile neutrino. It does, however, fix current problems in providing fits to all experimental estimates of the mean neutrino flux, and is compatible with the extensive evidence for solar neutrino flux variability. This fit involves a sterile neutrino associated only with the electron neutrino, but if there are steriles for each family, one would explain LSND’s results and provide hot dark matter, and the other could even be cold dark matter, possibly eliminating the need for dark energy.