Finally,the Italian Institute for Nuclear Physics (INFN) has endowed the 'Particle physics' area with a virtual workstation allowing users to visit the Gran Sasso National Laboratory, as well as a number of the photographic film and lead 'bricks' used in the OPERA experiment for detecting tau neutrinos
, and an interactive exhibit which reproduces particle collision.
In past experiments, physicists have measured the change of muon neutrinos to tau neutrinos
and electron neutrinos to muon neutrinos or tau neutrinos
Three types exist: muon neutrinos, electron neutrinos and tau neutrinos
These bizarre neutrino oscillations have now been confirmed at the Sudbury Neutrino Observatory--the first experiment that is not essentially blind to muon or tau neutrinos
that can be traced back to the Sun (S&T: September 2001, page 18).
The scientists had predicted there would be such a deficit if muon neutrinos became tau neutrinos
If the number of muon neutrinos observed in the Super-Kamiokande detector is smaller than the number right after firing, it can be concluded that the particles oscillated into tau neutrinos
, which would support the hypothesis that neutrinos have mass, they said.
These particles come in three types or flavours: electron, muon and tau neutrinos
SNO is the first that's also sensitive to the other two types, muon neutrinos and tau neutrinos
Therefore, the additional neutrino flow detected at Super-Kamiokande must be made of up muon and tau neutrinos
The probability that particles other than tau neutrinos
produced the four events is less than a tenth of a percent, says DONUT's Jacob Schneps of Tufts University in Medford, Mass.
The most likely explanation, physicists say, is that muon neutrinos, the type produced on high, were changing into tau neutrinos
, which the detector can't pick up.
Neutrinos come in three varieties--electron neutrinos, muon neutrinos and tau neutrinos
-- named for the other particles with which they are produced.