An Etymological Dictionary of Astronomy and Astrophysics

A neutrino produced in the collision of → cosmic rays
(typically → protons) with nuclei in the → upper atmosphere. This creates a shower of → hadrons, mostly → pions. The pions decay to a → muon and a muon neutrino. The muons decay to an → electron, another muon neutrino, and an electron neutrino.

See also: → atmospheric; → neutrino.