# Homework Help: Neutrino Annihilation

1. Apr 26, 2010

### jazznaz

1. The problem statement, all variables and given/known data

Is the following process a valid interaction?

$$\nu_\mu \bar{\nu}_e \rightarrow e^+ \mu$$

2. Relevant equations

none

3. The attempt at a solution

I'm not sure whether lepton number must be conserved at each vertex, or just for the overall process. I can draw a Feynmann diagram with a Z0 boson as the exchange particle, but I'm not convinced that this is correct.

2. Apr 26, 2010

### vela

Staff Emeritus
Yes, it is, but it's not mediated by the Z boson.

3. Apr 26, 2010

### jazznaz

In that case, it must be a photon?

4. Apr 26, 2010

### vela

Staff Emeritus
No. If the process involves neutrinos, it's a weak interaction.

5. Apr 26, 2010

### jazznaz

I think I'm being distracted by thinking that there's no transfer of charge between the initial and final states.

Had another go, and now have a diagram that looks like a scattering process with the exchange of a W+ boson.

6. Apr 26, 2010

### vela

Staff Emeritus
Sounds right!

7. Apr 26, 2010

Thanks!