[Richard777 (OP)]

The Compton Effect discovered in 1923 represents the interaction between a photon (x ray) and an electron. The interaction is elastic; the photon is “scattered”, and the electron “recoils”.

The interaction includes force. The “interactive force” may be represented as a vector. If two conditions apply, then the components will also give the Compton equation.

Energy is transferred from the x-ray photon to the electron. The medium of transfer is assumed to be a “transfer photon”. Components of the Compton Vector will give mass dilation (associated with the electron) and wave-length contraction (associated with the transfer photon).
Reference attached.

[alancalverd]

A force acts upon the transfer photon.

What is the origin and nature of this force? It's unknown to science!