# (Peskin and Schroeder) Numerator of vertex correction

1. May 26, 2013

### ndcat10

Hi I am studying qft with worldwidely used text, written by Peskin and Schroeder, An introduction to qft. I have trouble with the calculation of thr numerator on pp. 192. I got additional term $2m(z-xy)(mγ^μ - p^μ)$ between spinors, which seems not vanishing. Is there any idea to treat this problem? Thanks in advance

Last edited: May 26, 2013
2. May 28, 2013

### ndcat10

The problem is solved. Maybe I made mistake somewhere.(I calculated hundreds times to exaggerate.) Anyway thanks for reading this annoying post(at least I think I made another trash, but more than 100 people read this)