Hey,
I have been looking around for a good resource explaining the analytic properties of Feynman diagrams and their resulting amplitudes.
I think I understand in general what to expect (branch cuts for multiparticle states, poles for single particle states and bound states), but I'm not...
No, because the total of energy-momentum in the initial state is not zero, while the energy-momentum of the final state (which doesn't really exist here) is zero.
When you have particles in the initial state, you must have particles in the final state to carry the energy-momentum of the initial...
iceveela - i think it would be helpful if you tried to explain again what exactly you know, and what you want to find out.
The lifetime (or half-life which is simply the lifetime multiplied by a constant) is a property of the radioactive substance. If you do not know anything about the...
I think the important question is - what kind of theory exactly are you writing the Feynman diagrams for? You can have many Lagrangians with scalar fields that obey the Klein-Gordon equation (actually even fermions obey the KG equation - it's simply a statement about the relativistic...
The decay of a radioactive material is a process without memory - it means that the decay would look the same no matter how "old" the material is.
If you have 100 grams of this material, you define this as N_0 in the equation quoted above. If you want to find the half-life you should measure...
Hello,
this is the first time I post here, so if this is not in the correct section please let me know...
I'm working on solving the first final project in peskin - Radiation of gluon jets.
In this project we assume a simplified model for the gluon - it is a massive vector boson (with a...
Hi,
I can understand what confused you. Perhaps it has been said before me, but the thing here is that the Isospin symmetry people talk about in this context is an approximate symmetry. It is a good symmetry when you neglect the electroweak force. Then when you include corrections your...