Muon neutrino
| Composition | Elementary particle |
|---|---|
| Statistics | Fermionic |
| Generation | Second |
| Interactions | Weak, Gravity |
| Symbol |
ν μ |
| Antiparticle |
Muon antineutrino (ν μ) |
| Theorized | (1940s) |
| Discovered | Leon Lederman, Melvin Schwartz and Jack Steinberger (1962) |
| Mass | Small but non-zero. See neutrino mass. |
| Electric charge | 0 e |
| Color charge | No |
| Spin | 1⁄2 |
| Weak isospin | 1⁄2 |
| Weak hypercharge | −1 |
| Chirality | left-handed (for right-handed neutrinos, see sterile neutrino) |
The muon neutrino is a subatomic lepton elementary particle which has the symbol ν
μ and no net electric charge. Together with the muon it forms the second generation of leptons, hence its name muon neutrino. It was first hypothesized in the early 1940s by several people, and was discovered in 1962 by Leon Lederman, Melvin Schwartz and Jack Steinberger. The discovery was rewarded with the 1988 Nobel Prize in Physics.
Discovery
In 1962 Leon M. Lederman, Melvin Schwartz and Jack Steinberger established by performing an experiment at the Brookhaven National Laboratory[1] that more than one type of neutrino exists by first detecting interactions of the muon neutrino (already hypothesised with the name neutretto[2]), which earned them the 1988 Nobel Prize.[3]
Speed
In September 2011, OPERA researchers reported that muon neutrinos were apparently traveling at faster than light speed. This result was confirmed again in a second experiment in November 2011. These results have been viewed skeptically by the scientific community at large, and more experiments have/are investigating the phenomenon. In March 2012, the ICARUS team published results directly contradicting the results of OPERA.[4]
Later in July 2012 the apparent anomalous super-luminous propagation of neutrinos was traced to a faulty element of the fibre optic timing system in Gran-Sasso. After it was corrected the neutrinos appeared to travel with the speed of light within the errors of the experiment.[5]
See also
References
- ↑ G. Danby, J.-M. Gaillard, K. Goulianos, L. M. Lederman, N. B. Mistry, M. Schwartz, J. Steinberger (1962). "Observation of high-energy neutrino reactions and the existence of two kinds of neutrinos". Physical Review Letters 9: 36. Bibcode:1962PhRvL...9...36D. doi:10.1103/PhysRevLett.9.36.
- ↑ I.V. Anicin (2005). "The Neutrino – Its Past, Present and Future". SFIN (Institute of Physics, Belgrade) year XV, Series A: Conferences, No. A 2: 3–59. arXiv:physics/0503172. Bibcode:2005physics...3172A.
- ↑ "The Nobel Prize in Physics 1988". The Nobel Foundation. Retrieved 2010-02-11.
- ↑ M. Antonello et at. (2012). "Measurement of the neutrino velocity with the ICARUS detector at the CNGS beam". http://arxiv.org/abs/1203.3433v3
- ↑ "OPERA experiment reports anomaly in flight time of neutrinos from CERN to Gran Sasso (UPDATE 8 June 2012)". CERN press office. 8 June 2012. Retrieved 19 April 2013.
Further reading
- Leon M. Lederman (1988). "Observations in Particle Physics from Two Neutrinos to the Standard Model" (PDF). Nobel Lectures. The Nobel Foundation. Retrieved 2010-02-11.
- Melvin Schwartz (1988). "The First High Energy Neutrino Experiment" (PDF). Nobel Lectures. The Nobel Foundation. Retrieved 2010-02-11.
- Jack Steinberger (1988). "Experiments with High-Energy Neutrino Beams" (PDF). Nobel Lectures. The Nobel Foundation. Retrieved 2010-02-11.
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