On page 101 of Freedman and Van Proeyen's book on Supergravity they find the propagator of the gravitino, however I'm not sure how to work through the steps in (5.30), and hints or answers would be great help.
It begins with the equation of motion
γμνρ∂νΨρ=Jμ
and an ansatz solution of the form,
Ψμ(x)=−∫dDySμν(x−y)Jν(y).
Subbing this into the equation of motion gives,
iγμσρpσSρν(p)=iδμν−ipνΩμ(p)
in momentum space where Ωμ is a pure gauge term and contains all the dependence on pμ only. They then go on to produce an ansatz for this equation of the form,
iSρν(p)=A(p2)ηρνp+B(p2)γρpγν
which they then sub into the LHS of (5.28) to obtain the following,
iγμσρpσSρν(p)=Aγμσνppσ+(D−2)Bγμσpγνpσ=A(pμγσν−pσγμν)pσ+(D−2)B(−pμγσ+pσγμ)γνpσ+...=[A−(D−2)B](pμγσν−pσγμν)pσ+(D−2)Bp2δμν+...
where the ... represents terms that are proportional to the vector pν. I'm just unsure of how to go from the first to second and then to the third line of the above aligned equations.
This post imported from StackExchange Physics at 2019-07-09 21:53 (UTC), posted by SE-user huntercallum