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• Oscillation Neutrino Industry, of Maury Goodman
• The Neutrino Page of Juha Peltoniemi

	Spin	Masse	Magnetic spin	Cross section on nucleon at 1 GeV
	1/2	< 2.8 eV	< 5.8 10-20 MeV/T	around 10-38 cm2
	1/2	< 16=70 keV	< 4.3 10-20 MeV/T	environ 10-38 cm2
	1/2	< 18.2 MeV	< 3.1 10-17 MeV/T	around 10-38 cm2

There are 3 families of light neutrinos.

The neutrinos have all left helicity and anti-neutrinos have all right helicity (but the term "all" can be discussed!)

Neutrinos may be have a non zero mass Two recent results seem to indicate neutrinos oscillation: LSND (Usa) and SUPER-KAMIOKANDE (Japan)

Other experiments like Chooz, Chorus or Nomad did not find any evidence for neutrinos oscillation but they push further the limits on the two factors that control neutrinos oscillations: and .

Nota Bene:
The result of an experiment searching for neutrinos oscillation is often represented on a two dimensional graphics where is displayed versus . The first parameter is the difference of the squared masses oif the two types of neutrinos that oscillate in each other (simplified case of a two types neutrino oscillation). The second parameter is the maximal probability that a neutrino oscillates.

• LSND

  LSND is an experiment near Los Alamos, at a particle accelerator that delivers and anti whose energy is about 40 MeV. The LSND detector, which receives those neutrinos detected 22 anti-electrons which could come from anti interactionss and 40 electrons that could come from interactions. In the first case, only 22 anti-electrons were expected; in the second case only 5 electrons were expected. There is clearly more type than predicted. This result can be interpreted by oscillation to . The final result is a area where should be located the values of the two oscillation parameters et in order to to interpret as a neutrino oscillation this unexpected result of LSND.
  
  

• SUPER-KAMIOKANDE

  SUPER-KAMIOKANDE is located under a mountain in Kamioka mine, in Japan. It is a huge water tank (a cylinder 41 m by 39 m which contains about 50000 tons of pure water!) whose internal surface is covered with 11200 photomultipliers which detect the Cerenkov light of the particles coming for instance from a interaction with the water. Super-Kamiokande detects solar or atmospheric neutrinos whose energy is above 5 MeV. For what concerns solar neutrinos, Super-Kamiokande has already detected 44000 neutrinos, and this number is 37% of the expected number, confirming the results of Homestake, Gallex, etc... Below 1 GeV, 1158 events of type "interaction of a " were detected in 1997, but 1573 were expected. During the same period, 1231 events of type "interaction of a " were detected, and 1049 were expected. This seemed to indicate a lack of . One more time, the " neutrinos oscillation" interpretation could be made, if the oscillation parameters were in a precisely defined area.
  
  

• CHOOZ

  CHOOZ is a detector located near the Chooz nuclear plant, in France. The number of anti coming out the reactor and detected was about the expected number. This result allowed to establish a limit on neutrinos oscillations, that is an area in which oscillation between anti and anti does not exist. You can remark that the results of Kamiokande (the previous experiment before Super-Kamiokande) were not compatible with this exclusion area.
  
  

• NOMAD and CHORUS

  NOMAD and CHORUS are detectors located at CERN, near Geneva, under a neutrino beam of about 30 GeV. The two experiments are still analysing their data but the first results seems to indicate the absence of oscillation, for values above 4.2 10^-3.

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Last update: 26/06/1999 : http://wwwlapp.in2p3.fr/neutrinos/anresult.html

Didier Verkindt