# Electroweak Theory Down Quark Mass

## Main Question or Discussion Point

Hey,

A question on a paper asks to show how ψ(L) and ψ(R) decouple in the Dirac equation in the massless limit, after doing this we are told

'It is not possible to write a mass term for the down quark in electroweak theory - explain. How is the observed down quark mass then produced in this theory?'

I'm not quite sure what the questions means but I'm thinking it has something to do with the weak eigenstates or cabbibo mixing. I think the lecturer explained this but I didn't understand it, could anyone explain this to me?

Thanks,
SK

Last edited: