What is a neutrino?
What is a neutrino?
Neutrinos are similar to the more familiar electron, with one crucial difference: neutrinos do not carry electric charge. Because neutrinos are electrically neutral, they are not affected by the electromagnetic forces which act on electrons. Neutrinos are affected only by a "weak" sub-atomic force of much shorter range than electromagnetism, and are therefore able to pass through great distances in matter without being affected by it. If neutrinos have mass, they also interact gravitationally with other massive particles, but gravity is by far the weakest of the four known forces.
Three types of neutrinos are known; there is strong evidence that no additional neutrinos exist, unless their properties are unexpectedly very different from the known types. Each type or "flavor" of neutrino is related to a charged particle (which gives the corresponding neutrino its name). Hence, the "electron neutrino" is associated with the electron, and two other neutrinos are associated with heavier versions of the electron called the muon and the tau (elementary particles are frequently labelled with Greek letters, to confuse the layman). The table below lists the known types of neutrinos (and their electrically charged partners).
Neutrino Neutrinos have no electrical charge and almost never interact with other particles. Most neutrinos pass through the earth without ever interacting with a single atom. One way neutrinos are produced is during a neutron decay. In fact, it was through a careful study of this type of radioactive decay that physicists hypothesized the neutrino's existence. In fact the prediction of the neutrino and its subsequent discovery is a fine example of how science works through observation, hypothesising investigating and predicting to build upon current understanding.
In 1931 Wolfgang Pauli hypothesised the existence of the neutrino. After observations of certain radioactive decay he noticed that energy and momentum did not appear to be conserved. Newtons laws of conservation of energy and angular momentum, put forward over two centuries before, were not obeyed. Pauli suggested that this missing energy might be carried off, unseen, by a neutral particle which was escaping detection. In 1959 a particle fitting the expected characteristics of the neutrino was discovered. This neutrino is later determined to be the partner of the electron. Since then 2 other types of neutrinos have being discovered, the muon and the tau.
Neutrino ne nm nt Charged Partner
electron (e) muon
(m) tau
(t)
Neutrinos are similar to the more familiar electron, with one crucial difference: neutrinos do not carry electric charge. Because neutrinos are electrically neutral, they are not affected by the electromagnetic forces which act on electrons. Neutrinos are affected only by a "weak" sub-atomic force of much shorter range than electromagnetism, and are therefore able to pass through great distances in matter without being affected by it. If neutrinos have mass, they also interact gravitationally with other massive particles, but gravity is by far the weakest of the four known forces.
Three types of neutrinos are known; there is strong evidence that no additional neutrinos exist, unless their properties are unexpectedly very different from the known types. Each type or "flavor" of neutrino is related to a charged particle (which gives the corresponding neutrino its name). Hence, the "electron neutrino" is associated with the electron, and two other neutrinos are associated with heavier versions of the electron called the muon and the tau (elementary particles are frequently labelled with Greek letters, to confuse the layman). The table below lists the known types of neutrinos (and their electrically charged partners).
| Neutrino |
| Neutrinos have no electrical charge and almost never interact with other particles. Most neutrinos pass through the earth without ever interacting with a single atom. One way neutrinos are produced is during a neutron decay. In fact, it was through a careful study of this type of radioactive decay that physicists hypothesized the neutrino's existence. In fact the prediction of the neutrino and its subsequent discovery is a fine example of how science works through observation, hypothesising investigating and predicting to build upon current understanding. In 1931 Wolfgang Pauli hypothesised the existence of the neutrino. After observations of certain radioactive decay he noticed that energy and momentum did not appear to be conserved. Newtons laws of conservation of energy and angular momentum, put forward over two centuries before, were not obeyed. Pauli suggested that this missing energy might be carried off, unseen, by a neutral particle which was escaping detection. In 1959 a particle fitting the expected characteristics of the neutrino was discovered. This neutrino is later determined to be the partner of the electron. Since then 2 other types of neutrinos have being discovered, the muon and the tau. |
| Neutrino | ne | nm | nt | |||
| Charged Partner | electron (e) | muon (m) | tau (t) |
