Wilsonian effective field theory

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SUMMARY

The discussion centers on Wilsonian effective field theory as outlined in Chapter 29 of Srednicki's textbook. Participants seek clarification on the treatment of external and internal lines in Feynman diagrams, specifically why diagrams with external momenta \( k < \Lambda \) and internal momenta \( k > \Lambda \) are used. The conversation highlights the distinction between the six-point vertex function and the six-point coupling constant \( c_6 \), emphasizing the conceptual framework of effective field theory in quantum field theory (QFT).

PREREQUISITES
  • Understanding of Feynman diagrams in quantum field theory
  • Familiarity with effective field theory concepts
  • Knowledge of coupling constants and vertex functions
  • Basic grasp of the renormalization group and momentum scales
NEXT STEPS
  • Study the derivation of effective field theories in quantum field theory
  • Learn about the renormalization group flow and its implications
  • Explore the role of coupling constants in perturbative expansions
  • Examine the differences between effective and fundamental theories in particle physics
USEFUL FOR

This discussion is beneficial for theoretical physicists, graduate students in quantum field theory, and researchers interested in the applications of effective field theories in particle physics.

LAHLH
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Hi,

could anyone explain to me why in effective field theory (as in ch29 srednicki), you look at diagrams with only k&lt;\Lambda as external lines and k&gt;\Lambda for your interal lines? why do these diagrams with say, 6 external legs of this type, equate to the constant c_6 say? In previous chapters of the book it's usually the exact 6 point vertex function that would equate to such a diagram, not the 6 point coupling constant itself etc.

I understand the math behind what Srednicki is doing, but not sure I understand what he is actually trying to do here, so all comments on this whole topic in QFT would be great.

thanks
 
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I second that! :-)
 
ansgar said:
I second that! :-)

Hah, anyone out there know how this stuff works?
 

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