Eq. 9.124 has 3 steps. The first one gives 0 propagator for ε goes to 0. The final step, the one with Z gives infinity. Can anyone post the correct steps? Is there anything wrong in previews equations? It is important for me to learn the Ryder's book method. I have an exam in 10 days(adsbygoogle = window.adsbygoogle || []).push({});

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# Ryder QFT 2nd ed. page 341 misprint?

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