Neutrino Annihilation: Validity of Interaction and Lepton Number Conservation

[jazznaz]

Homework Statement

Is the following process a valid interaction?

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

Homework Equations

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 Feynman diagram with a Z0 boson as the exchange particle, but I'm not convinced that this is correct.

 

[vela]

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

 

[jazznaz]

In that case, it must be a photon?

 

[vela]

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

 

[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.

 

[vela]

Sounds right!

 

[jazznaz]

Thanks!