  We study formal deformations of a crossed product $S(V)#_f G$, of a
polynomial algebra with a group, induced from a universal deformation formula
introduced by Witherspoon. These deformations arise from braided actions of
Hopf algebras generated by automorphisms and skew derivations. We show that
they are nontrivial in the characteristic free context, even if $G$ is
infinite, by showing that their infinitesimals are not coboundaries. For this
we construct a new complex which computes the Hochschild cohomology of $S(V)#_f
G$.
