# Neutrinos: Partner of electrons?

1. Nov 9, 2006

### Swapnil

I am new to these particles called neutrinos but I was wondering why are they called the "partners" of electrons?

2. Nov 10, 2006

### dextercioby

Massless or not, the electronic neutrino behaves like electrons when subject to weak interactions. They're from the same family.

Daniel.

3. Nov 10, 2006

### arivero

More exactly, left neutrinos and left electrons are the two sides of a "weak isospin" doublet. Under the action of the W particle, one transforms into the another.

4. Nov 10, 2006

### Swapnil

So do neutrinos behave like electrons ONLY in the context of weak interactions? Are any other situations where they would behave the same?

5. Nov 10, 2006

### arivero

Is the only non trivial situation. Of course both particles are neutral respect to colour.

6. Nov 11, 2006

### Meir Achuz

In the standard model, leptons occur in three doublets. These are:
The electron and the "electron neutrino".
The muon and the "mu neutrino".
The tau and the "tau neutrino".
In each case, the first lepton in the pair, is negatively charged and much heavier than its neutral neutrino.

7. Nov 11, 2006

### CarlB

I realize that this is what everyone does, but I hate talking about the "electron neutrino" as being much lighter than the electron when the "electron neutrino" is not an eigenstate of mass. The neutrino mass eigenstates are $$\nu_1, \nu_2, \nu_3$$, and I think the whole setup is much more elegant if thes are considered the particles of the 1st, 2nd and 3rd generations.

Otherwise, one treats the quark and lepton mixing in very different terms. If it had been known from the beginning that the neutrinos, like the quarks and electrons, have mass, the notation now would match the notation for the mixed quarks. Instead, the standard model assumed massless neutrinos and here we are.

Carl

Last edited: Nov 11, 2006
8. Nov 13, 2006

### Meir Achuz

The electron neutrino is the neutrino that couples with the electron in beta decay. That it is not a mass eigenstate, is a different answer to a different question. We have to learn not to hate.