Antineutrino

Infobox Particle
bgcolour =
name = Antineutrino


caption =
num_types = 3 - electron, muon and tau
composition = Elementary particle
family = Fermion
group = Lepton, Anti-Lepton
generation =
interaction = weak force and gravity
particle =
antiparticle = Neutrino
theorized = 1930
discovered = 1956
symbol = SubatomicParticle|Electron antineutrino,SubatomicParticle|Muon antineutrino, SubatomicParticle|Tau antineutrino
mass =
decay_time =
decay_particle =
electric_charge = 0
color_charge = 0
spin = 1/2
lepton_number = -1
num_spin_states =

In physics, antineutrinos, the antiparticles of neutrinos, are neutral particles produced in nuclear beta decay. These are emitted in beta particle emissions, where a neutron turns into a proton. They have a spin of 1/2, and they are part of the lepton family of particles. The antineutrinos observed so far all have right-handed helicity (i.e., only one of the one possible spin states has ever been seen), while the neutrinos are left-handed. Antineutrinos interact with other matter only through the gravitational and weak forces, making them very difficult to detect experimentally. Neutrino oscillation experiments indicate that antineutrinos have mass, but beta decay experiments constrain that mass to be very small.

Because antineutrinos and neutrinos are neutral particles it is possible that they are actually the same particle. Particles which have this property are known as Majorana particles. If neutrinos are indeed Majorana particles then the neutrinoless double beta decay process is allowed. Several experiments have been proposed to search for this process.

Researchers around the world have begun to investigate the possibility of using antineutrinos for reactor monitoring in the context of nonproliferation. [LLNL/SNL Applied Antineutrino Physics Project. LLNL-WEB-204112 (2006): http://neutrinos.llnl.gov/] [Applied Antineutrino Physics 2007 workshop: http://www.apc.univ-paris7.fr/AAP2007/] [DOE/Lawrence Livermore National Laboratory (2008, March 13). New Tool To Monitor Nuclear Reactors Developed. ScienceDaily. Retrieved March 16, 2008, from http://www.sciencedaily.com/releases/2008/03/080313091522.htm]

ee also

* Neutrino
* Kamioka Liquid Scintillator Antineutrino Detector

References

External links

* [http://www.mpi-hd.mpg.de/non_acc/POSITIVE-EVID/NEW-2004/PL586-2004.pdf Search for neutrinoless double beta decay with enriched 76Ge in Gran Sasso 1990–2003]