出典:Wikipedia
出典:『Wikipedia』 (2011/06/02 19:50 UTC 版)
A neutrino (Italian pronunciation: [neuˈtriːno], meaning "small neutral one"; English pronunciation: /njuːˈtriːnoʊ/) is an elementary particle that usually travels close to the speed of light, is electrically neutral, and is able to pass through ordinary matter almost unaffected. This makes neutrinos extremely difficult to detect. Neutrinos have a very small, but nonzero mass. They are denoted by the Greek letter ν (nu).