# A Gamma - traceless

#### filip97

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#### dextercioby

Homework Helper
Perhaps if we ping @samalkhaiat , you can get an answer. :) It may very well be the one on the SE website, though.

#### samalkhaiat

It may very well be the one on the SE website, though.
It is. If he could not understand the reasoning in the SE website, he may not be able to understand my answer in the following

#### filip97

Ok, it is clearer. But why 1/2 component carried with divergence of Dirac spinor ? (This removing ghosts ?)

#### samalkhaiat

Ok, it is clearer.
Is it? Then why are you asking this?
But why 1/2 component carried with divergence of Dirac spinor ?
First: $\psi^{\mu}(x)$ is a spinor-vector field. It describes spin-3/2 particle and its anti-particle. It is NOT a Dirac spinor (Dirac spinor field describes spin-1/2 particle and its anti-particle).
Second: The divergence of $\psi^{\mu}(x)$ IS a Dirac spinor because (as I have already explained in the other thread) $\partial_{\mu}\psi^{\mu}$ satisfies the Dirac equation. In other words, the field $\psi (x) \equiv \partial_{\mu}\psi^{\mu}(x)$ represents one of the two spin-1/2 components of the spinor-vector field $\psi^{\mu}(x)$. All of this was explained in the other thread.
(This removing ghosts ?)
Which ghosts are these?

EDIT

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#### samalkhaiat

EDIT
Non of your links explain the matter better and/or easier than I did in the other thread. And your second link contains wrong as well as confused statements.

#### filip97

filip97
Can we raising and lowering indices of mwtric spinor with 2-contravariant or 2-covariant with metric tensor ? I think that we can do this with sigma(mu,nu) this write in Sexl Urbantke book of group representation. I was post this question because dont clear ho we contract Dirac equation with gamma(mu). Thanks a lot !!!

"Gamma - traceless"

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