Beyond the Classical Approximation

  • Carlo M. Becchi
  • Giovanni Ridolfi
Part of the UNITEXT for Physics book series (UNITEXTPH)


We have seen in Chap.  4 that physical transition amplitudes correspond to amputated connected diagrams with a given number of external lines. In general, these diagrams contain loops as discussed in Sect.  4.5. Following the Feynman rules given in Chap.  4, a generic connected diagram can be built as a tree diagram whose vertices are either point-like, or sub-diagrams with loops. We shall call these vertices effective vertices: an effective vertex is a sub-diagram that cannot be broken into two parts cutting a single internal line.


Higgs Mass Goldstone Boson Vacuum Polarization External Line Gauge Choice 
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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  1. 1.University of GenovaGenovaItaly

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