I tried to derive eqn (9.94) on page 192 of the second edition of Mandl and Shaw QFT and failed. Can someone help me see what I am doing wrong?(adsbygoogle = window.adsbygoogle || []).push({});

Ignoring factors that do not change from eqn (9.92) to eqn (9.94), noting that f(k) has been set to 1, and dropping terms linear in k and k squared as described in the text, I get:

[tex]\frac{\gamma^{\alpha}(\not{p'}+m)\gamma^{\mu}(\not{p}+m)\gamma_{\alpha}}{((p'-k)^2 - m^2)((p-k)^2 - m^2)}[/tex]

[tex] = \gamma^{\mu}\frac{(-2p'p)}{(-2p'k)(-2pk)} + \frac{4m(p' + p)^{\mu}}{(-2p'k)(-2pk)} + \gamma^{\mu}\frac{(-2m^2)}{(-2p'k)(-2pk)}[/tex]

The first term on the right hand side is the same as in the book, but divided by -2. Perhaps the other two terms combine in some way to fix it up, but I don't see it. I also don't see what terms are meant by the author when he says "the dots indicate terms which are finite in the limit [itex]\lambda \rightarrow 0[/itex]" since none of the terms involve [itex]\lambda[/itex].

**Physics Forums - The Fusion of Science and Community**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Mandl & Shaw eqn (9.94)

Loading...

Similar Threads - Mandl Shaw | Date |
---|---|

Mandl & Shaw eqn (15.28) | Aug 23, 2013 |

Mandl & Shaw page 361 | Aug 3, 2013 |

Mandl & Shaw page 263 | Jul 29, 2013 |

Mandl & Shaw page 297 | Jul 25, 2013 |

Mandl & Shaw eqn (12.123) | Jul 24, 2013 |

**Physics Forums - The Fusion of Science and Community**