The annihilation of a neutrino-anti-neutrino pair into photons and the neutrino density in the universe

✍ Scribed by T. de Graaf; H.A. Tolhoek

• Publisher: Elsevier Science
• Year: 1966
• Weight: 512 KB
• Volume: 81
• Category: Article
• ISSN: 0029-5582
• DOI: 10.1016/s0029-5582(66)80045-7

✦ Synopsis

The cross section for the process ve÷~ e -~-3y is calculated in the low-energy approximation, assuming a universal Fermi interaction. It is found that cr ~ 9.5 × 10 -60 ((o/m) 1° cm-" in the c.m. system of the (v, ~)-pair

If it is assumed that the universe contains degenerate Fermi gases of both neutrinos and antineutrinos, the above mentioned process provides the most important way for mutual annihilation of these gases. It results from our calculations that the rate of annihilation of neutrinos and anti-neutrinos is so small for any reasonable Fermi energy of the Fermi gases (,smaller than, say, 100 eV), that both degenerate Fermi gases could coexist with negligible annihilation during a time of, e.g., 1.3 × 10 ~° y, typical for the present state of the universe.