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.

 

[m2003]

I understand your confusion about the W- and W+ particles in weak interactions. The key to determining which weak interaction involves which particle is to look at the charge conservation law. W- carries a negative charge of -1, while W+ carries a positive charge of +1. Therefore, in any weak interaction, the total charge before and after the interaction must remain the same. For example, in beta minus decay, the initial state has a neutral neutron (charge 0) and the final state has a positively charged proton (charge +1) and a negatively charged electron (charge -1). This satisfies the charge conservation law, as the total charge before and after the interaction is 0. Similarly, in beta plus decay, the initial state has a positively charged proton (charge +1) and the final state has a neutral neutron (charge 0) and a positively charged positron (charge +1), satisfying the charge conservation law.

In an unknown reaction, you can use this charge conservation law to determine which weak interaction is involved. If the initial and final states have the same total charge, then W- is involved. If the final state has a higher total charge than the initial state, then W+ is involved. I hope this helps clarify your confusion. Please let me know if you have any further questions.