Can a W boson decay to a u quark and anti-s quark?

[Ajihood]

Hey Guys,

Just a quick question. Can a W boson decay to a u and anti s or does it have to decay to a quark and anti-quark of the same generation?

Thanks!

 

[fzero]

The weak couplings are determined by the CKM matrix, which mixes the down type quarks between generations. So the $$W^+$$ can decay to $$u\bar{d}$$, $$u\bar{s}$$, $$u\bar{b}$$, as well as the corresponding channels involving the charm quark.

 

[Ajihood]

Thanks for that fzero. I thought it could because of the CKM matrix but I have only seen examples of where it decays to u and anti d etc so I was a little worried that there may be more there I haven't learned yet. Thanks again :)