artificial nuclear reactions in nuclear reactors, nuclear bombs, or particle accelerators.natural nuclear reactions such as those that take place in the core of a star.beta decay of atomic nuclei or hadrons,.Neutrinos are created by various radioactive decays the following list is not exhaustive, but includes some of those processes: To conserve total lepton number (in nuclear beta decay), electron neutrinos only appear together with positrons (anti-electrons) or electron-antineutrinos, whereas electron antineutrinos only appear with electrons or electron neutrinos. Antineutrinos are distinguished from neutrinos by having opposite-signed lepton number and weak isospin, and right-handed instead of left-handed chirality. įor each neutrino, there also exists a corresponding antiparticle, called an antineutrino, which also has spin of 1 / 2 and no electric charge. Although only differences between squares of the three mass values are known as of 2019, cosmological observations imply that the sum of the three masses (< 2.14 × 10 −37 kg) must be less than one millionth that of the electron mass (9.11 × 10 −31 kg). For example, an electron neutrino produced in a beta decay reaction may interact in a distant detector as a muon or tau neutrino. Similar to some other neutral particles, neutrinos oscillate between different flavors in flight as a consequence. A neutrino created with a specific flavor is a specific mixture of all three mass states (a quantum superposition). Although neutrinos were long believed to be massless, it is now known that there are three discrete neutrino masses with different tiny values, but the three masses do not uniquely correspond to the three flavors. Τ), in association with the corresponding charged lepton. Weak interactions create neutrinos in one of three leptonic flavors: electron neutrinos ( Thus, neutrinos typically pass through normal matter unimpeded and undetected. The weak force has a very short range, the gravitational interaction is extremely weak due to the very small mass of the neutrino, and neutrinos do not participate in the strong interaction. The rest mass of the neutrino is much smaller than that of the other known elementary particles excluding massless particles. The neutrino is so named because it is electrically neutral and because its rest mass is so small ( -ino) that it was long thought to be zero. < 0.120 eV ( < 2.14 × 10 −37 kg), 95% confidence level, sum of 3 "flavours" Ī neutrino ( / nj uː ˈ t r iː n oʊ/ new- TREE-noh denoted by the Greek letter ν) is a fermion (an elementary particle with spin of 1 / 2) that interacts only via the weak interaction and gravity. Μ: Leon Lederman, Melvin Schwartz and Jack Steinberger (1962)
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