GIM mechanism

I can see how the charge is conserved in the overall diagram but I can not understand how it is conserved at the up to anti-down vertex.


In your diagrams, time moves to the right. The four vertices that make up the "box" aren't well-ordered in time. So the vertex involving the anti-down is one of the reactions

$$ \bar d u \to W^+ \qquad\text{or}\qquad \bar d \to \bar u W^+ $$

These vertices conserve both electric charge and baryon number.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.