Estimation of an Upper Limit on the Density of Relic Neutrinos in the Sun via the Solar ${}^8$B Neutrino Flux

Abstract

Relic neutrinos from the early universe are predicted to have a relatively large number density, but extremely low energies. Hence, the only possible interaction proceeds via neutrino capture on beta-decaying nuclei. In case relic neutrinos are captured by beta-decaying nuclei in the Sun, the neutrinos normally emerging from the decay of these nuclei will be missing from the overall number of solar neutrinos registered in neutrino experiments. Within the Sun, ${}^8\mathrm{B}$ and three nuclei from the CNO cycle are found to be suitable for this kind of process. Their cross section as well as the possible impact on the observed number of solar neutrinos are discussed. Assuming standard neutrino oscillations, no deviations of neutrino flux measurements from the predictions of the solar standard model are observed and upper limits are derived accordingly.

References in corpus (11)

• Measurement of the rate of nu_e + d --> p + p + e^- interactions produced by 8B solar neutrinos at the Sudbury Neutrino Observatory
• Measurement of the Total Active 8B Solar Neutrino Flux at the Sudbury Neutrino Observatory with Enhanced Neutral Current Sensitivity
• An improved upper limit on the neutrino mass from a direct kinematic method by KATRIN
• Solar neutrino measurements in Super-Kamiokande-II
• Combined Analysis of all Three Phases of Solar Neutrino Data from the Sudbury Neutrino Observatory
• Solar neutrino results in Super-Kamiokande-III
• Independent Measurement of the Total Active 8B Solar Neutrino Flux Using an Array of 3He Proportional Counters at the Sudbury Neutrino Observatory
• Measurement of the solar 8B neutrino rate with a liquid scintillator target and 3 MeV energy threshold in the Borexino detector
• Development of a Relic Neutrino Detection Experiment at PTOLEMY: Princeton Tritium Observatory for Light, Early-Universe, Massive-Neutrino Yield
• Improved measurement of ${}^8$B solar neutrinos with 1.5 kt y of Borexino exposure
• Probing Low Energy Neutrino Backgrounds with Neutrino Capture on Beta Decaying Nuclei