If understand correctly from you, there are 3 ( electron,muon and tau ) as far you site , is beautiful intimidating, I wonder how many experiment have been done to create such mass of data .
The ongoing experiments with neutrinos began over 40 years ago with the primitive neutrino detector deployed by Nobel laureate Ray Davis and his team at the Homestake mine in South Dakota. It consisted of a large tank of perchloroethane (dry cleaning fluid) and a means for processing and counting the number of argon atoms produced when a neutrino of a particular flavor interacted with the chlorine atoms in the perchloroethane molecules. This kicked off the thirty year Mystery of the Missing Solar Neutrinos, a riveting saga which eventually led to both the discovery of the missing solar neutrino flux, and the discovery of neutrino oscillations and the two other flavors of neutrinos, not to mention fixing a precise value for the age of our sun.
One of Ray's former colleagues at Homestake is still a close personal friend.
I rate this discovery to be one of the greatest in the history of science, rating right up there with Isaac Newton's theory of universal gravitation. Such discoveries happen seldom, but change our view of the universe in a profound way. Because of Newton, we no longer wonder whether the Earth's orbit may decay, crashing into the Sun. Because of Ray, we no longer wonder if the Sun will go red giant tomorrow.
All because of a near insignificant, and near massless particle proposed by Wolfgang Pauli before an audience many of whom doubted its existence. Such things still happen today. Near insignificant scientific discrepancies can matter a great deal.
And so, if we were ever to travel to any of the newly discovered exoplanets orbiting distant stars, a knowledge of the dynamics of the neutrino will no doubt continue to be an area of science that is of intense interest.