Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This question is mostly about how to interpret notation used in Particle Physics. I am given that at lowest order the rate of $b\rightarrow s\gamma$ is proportional to $\langle B_p|b^\dagger b|B_p\rangle$ where $p$ is either u or d labels and $b$, $b^\dagger$ are creation annhilation operators. However, I am unable to understand this notation. For some initial state transforming to a final state isn't the amplitude given by $\langle \mbox{final}|\hat{O}|\mbox{initial}\rangle$. Shouldn't the amplitude be in this case $\langle s\gamma|b^\dagger b|b\rangle$ or something?

So what does the provided matrix element mean, exactly?

share|cite|improve this question
What does the state $|B_p\rangle$ represent? Is that a baryon state? – David Z Dec 19 '11 at 0:56
@DavidZaslavsky Yes It may be $B^- (b\bar{u}) ,B^0(b\bar{d})$ etc. $B_p$ means a b quark with a u/d quark – yayu Dec 19 '11 at 1:19
Oh, B mesons. Got it. – David Z Dec 19 '11 at 2:46
Any chance you could provide a reference to where you saw this? I've been thinking about it and there does appear to be something missing. – David Z Dec 19 '11 at 6:59

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.