Verifying Ward Identity: Need Help With Algebra?

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SUMMARY

The discussion focuses on verifying the Ward identity as presented in Peskin's book on page 160, specifically in equation 5.74. The user initially struggled with the algebra required for this verification but ultimately succeeded by applying the equation of motion, leading to the conclusion that the expression simplifies to zero. Key elements include the use of momentum conservation, represented as \( k' - k = p - p' \), and the manipulation of spinor products, resulting in the expression \( \bar{u}(p') (\not p - \not p') u(p') = 0 \).

PREREQUISITES
  • Understanding of quantum field theory concepts, particularly the Ward identity.
  • Familiarity with Peskin's "An Introduction to Quantum Field Theory".
  • Knowledge of algebraic manipulation in the context of particle physics.
  • Basic understanding of momentum conservation in quantum mechanics.
NEXT STEPS
  • Review the derivation of the Ward identity in Peskin's text.
  • Study the implications of momentum conservation in quantum field theory.
  • Learn about the equations of motion for spinors in quantum mechanics.
  • Explore advanced algebra techniques used in particle physics calculations.
USEFUL FOR

Students and researchers in quantum field theory, particularly those interested in the mathematical foundations of particle interactions and the verification of theoretical identities.

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In peskin p. 160 forth paragraph they say to verefy Ward identity in equation 5.74.
I don't succeed, they say some algebra is needed. I conjecture that this some algebra is what i miss.
Any help will be appreciated - thanks a lot.
 
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Remember that ##\not k \not k = 0## and that from momentum conservation ## k' - k = p - p'##

So you may end up with something like ##\bar{u}(p') (\not p - \not p') u(p')##, which you can use equation of motion to get ##m-m = 0##.
 
Hurray... It got solved.
Many many thank's.
 

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