| Chronology | Current Month | Current Thread | Current Date |
| [Year List] [Month List (current year)] | [Date Index] [Thread Index] | [Thread Prev] [Thread Next] | [Date Prev] [Date Next] |
I agree with the comments by Dan. I'm presently teaching a
particle physics course for juniors and seniors, and I've decided to use
Dan's Option #3. The official text for the course is Griffiths'
"Introduction to Elementary Particles" which provides the clearest
treatment, but it suffers from the weaknesses described by Dan. In fact,
for the first half of the course, I've spent most of the time developing a
lot of the machinery (e.g.,time dependent perturbation theory in the
interaction picture) and background (e.g., non-relativistic QED) which
bridges the gap between the physics they know (1st semester quantum) and
particle physics. In this way, I hope to provide some deeper understanding
of what the Feynman diagrams really mean and motivation for the Feynman
rules that Griffiths just writes down.
Sounds good, if the students are really ready for that kind of rigor.
But it's not exactly what I had in mind. What I prefer is a more
intuitive explanation of Feynman rules in position space where the
rules pretty much are what one would guess. For instance, the expression
for an external line carrying momentum p, heading into a vertex x,
is just the plane-wave function e^(-ip.x) (4-vector dot product),
which gives the amplitude for finding such a particle at x. This
really isn't so mysterious. The propagator is harder to motivate,
but it's really about the only thing it can be that's Lorentz
invariant. Once students understand the position-space formulation
it's pretty easy to rearrange things to obtain the momentum formulation
that's presented in Griffiths and everywhere else.
-dan