# Association between W Boson Decay and Leptons

1. Feb 23, 2016

### TDanskin

As a physics A Level student, I am interested in understanding particle physics. Recently I have read that a W boson, as a relatively heavy particle, decays into one of three charged anti-leptons, and one of the three neutrinos. If a W boson decays to form an anti-tau lepton, it will also form a tau neutrino. Is the association of electrons, muons and tau particles with their 'corresponding' neutrinos purely based on this decay of W bosons?

2. Feb 23, 2016

### ohwilleke

W bosons decay into every possible combination of particles that is permitted by the conservation laws.

3. Feb 23, 2016

### TDanskin

Thanks so is the decay of a W boson not restricted to an anti-lepton and it's neutrino?

4. Feb 23, 2016

### Orodruin

Staff Emeritus
You can also decay into quarks.

If you decay into a (anti-)lepton, the produced neutrino is always of the same flavour. This is what defines neutrino flavour.

Edit: And by "you" I mean the W ...

5. Feb 23, 2016

### Staff: Mentor

The other option is quark plus antiquark.
Or via other process that involve real or virtual W bosons. In the Standard Model, those are the only interactions that convert elementary particles into other particles.

Edit: For clarification: particle+antiparticle -> something else is not meant here, that happens via other bosons as well.

Last edited: Feb 23, 2016
6. Feb 23, 2016

### Orodruin

Staff Emeritus
I could have sworn Peskin-Schröder had an early example of electromagnetic $e^+e^-\rightarrow\mu^+\mu^-$ scattering ...
Anyway, I know what you mean, but an entry level student might not.

7. Feb 23, 2016

### ohwilleke

8. Feb 24, 2016

### TDanskin

Thank you, this is all really useful :-)