I would like to know if there is any easy way to perform the operator product expansion of the following
:∂Xμˉ∂XνeikρXρ(z,ˉz)::∂Xαˉ∂XβeikσXσ(w,ˉw):
I tried to find all the contraction terms and use wick's theorem, but it turns out to be a mission impossible. How to compute it quickly?