Content deleted Content added
m →Relation to the S-matrix: The \right \left brackets are unnecessarily large for this equation. |
|||
Line 75:
</math>
where by convention the momenta are directed inwards into the diagram. A useful quantity to calculate when calculating scattering amplitudes is the matrix element <math>\mathcal M</math> which is defined from the S-matrix via
<math display="block">\langle f| S - 1 |i\rangle = i(2\pi)^4 \delta^4{\
where <math>p_i</math> are the external momenta. From the LSZ reduction formula it then follows that the matrix element is equivalent to the amputated connected momentum space correlation function with properly orientated external momenta<ref>{{cite book|last1=Mandl|first1=F.| last2=Shaw|first2=G.| date=2010| title=Quantum Field Theory|publisher=John Wiley & Sons| chapter=12|edition=2| page=254| isbn=9780471496847}}</ref>
<math display="block">
| |||