The decomposition of 4-point correlation functions into conformal
partial waves is a central tool in the study of conformal field theory.
We compute these partial waves for scalar operators in Minkowski
momentum space, and find a closed-form result valid in arbitrary
space-time dimension d \geq 3d≥3
(including non-integer dd).
Each conformal partial wave is expressed as a sum over ordinary spin
partial waves, and the coefficients of this sum factorize into a product
of vertex functions that only depend on the conformal data of the
incoming, respectively outgoing operators. As a simple example, we apply
this conformal partial wave decomposition to the scalar box integral in
d = 4d=4
dimensions.