Diffuse supernova neutrino background

The Diffuse Supernova Neutrino Background (DSNB) is a theoretical population of neutrinos (and anti-neutrinos) originating from all of the supernovae events which have occurred throughout the Universe. An individual supernova will release as many as ${\displaystyle 10^{57}}$ neutrinos, which is detectable as a short burst of events on Earth provided that the supernova occurred within our own galaxy, the only current example of which is SN1987A. In contrast the DSNB is a continuous source of neutrino events for which currently only experimental upper limits exist e.g. from the Super Kamiokande experiment at a level of ${\displaystyle 2.9{\bar {\nu _{e}}}\,\mathrm {cm} ^{-2}\,\mathrm {s} ^{-1}}$ for neutrino energies above 17.3 MeV. Theoretical predictions for the flux of the DSNB on Earth are difficult as they depend on many different parameters and assumptions e.g. the rate of supernovae events in the Universe as a function of time, the star formation rate and the neutrino spectrum from each supernova. However even given these uncertainties the DSNB flux should not be more than an order of magnitude below the current experimental bound, and so will be detectable in the near future.

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