In almost all the books on field theory I've seen, the authors list out the different types of quantities you can construct from the Dirac spinors and the gamma matrices, but I'm confused by how these work. For instance, if $$\overline\psi\gamma^5\psi$$ is a pseudoscalar, how can $$\overline\psi\gamma^\mu\psi$$ be a vector? Aren't gamma-5 and gamma-mu just different matrices? How do you get a vector out of the second operation?(adsbygoogle = window.adsbygoogle || []).push({});

Thanks!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

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

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

# Dirac eq gamma matrices question

**Physics Forums | Science Articles, Homework Help, Discussion**