Solving Weak Interactions: W- vs W+

[fabbo]

Well its not really a homework question but I have looked through the tutorials and am still at a loss.

Homework Statement

During weak interactions the particle exchanged is either W- W+ or Z0. The thing is, I get confused which weak interactions involve W- and which involve W+. I know beta minus decay is W- and beta plus W+ but how do I work it out for an unknown reaction?

Homework Equations

Is charge conservation involved, if so how?

Any guidance would be much appreciated.

 

[Kurdt]

W bosons are primarily seen in quarks flavour changes. I take it you are doing A-levels, or equivalent. If you are don't worry about the rules and just learn the few reactions you're given. I say this because W bosons can either be emited or absorbed which makes it a bit more difficult.