Grand Unified Neutrino Spectrum at Earth: Sources and Spectral Components

Abstract

We briefly review the dominant neutrino fluxes at Earth from different sources and present the Grand Unified Neutrino Spectrum ranging from meV to PeV energies. For each energy band and source, we discuss both theoretical expectations and experimental data. This compact review should be useful as a brief reference to those interested in neutrino astronomy, fundamental particle physics, dark-matter detection, high-energy astrophysics, geophysics, and other related topics.

Taking Neutrino Pictures via Electrons

“…The hep neutrinos are less studied experimentally because their flux is rather suppressed compared to that of 8 B neutrinos. The GS98 prediction for the flux of hep neutrinos is 0.8 × 10 4 cm −2 s −1 compared to 5.46 × 10 6 cm −2 s −1 for the 8 B neutrinos [27]. So apart from the magnitudes and spectral shapes of the fluxes, the physics for 8 B and hep neutrinos is essentially the same and we shall use the same formulas as in the previous section.…”

“…B. For the energy distribution we take in both cases the GS98 prediction taken from [27] with f 8B 0 = 5.46 × 10 6 cm −2 s −1 . We will also include neutrino oscillations into the picture at this point.…”

“…Figure 9: The normalised solar neutrino energy spectrum for 8 B and hep neutrinos taken from [27]. For the hep neutrinos we take the average of the two data sets provided there.…”

“…As a reminder before we continue, the energy distribution of the produced neutrinos is to a good approximation independent from the production zone and we will use the energy distributions from [27]. For completeness and convenience of the reader we show the normalised 8 B and hep energy distributions in Fig.…”

“…B.4. The energy distribution and flux factor f 8B 0 = 5.46 × 10 6 cm −2 s −1 is the GS98 result from [27]. Like in the previous section we will also use here a constant electron neutrino survival probability P ee = 0.37 [28] and use for the differential cross section in the above formula…”