# Neutrino Annihilation

## Homework Statement

Is the following process a valid interaction?

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

none

## 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.

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

In that case, it must be a photon?

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

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.

vela
Staff Emeritus