== Formula for photon scattering WRONG == 

 The article contains an error in Relationship to Other Constants, when it claims the non-reduced Compton wavelength applies in the Thomson scattering cross section.  Actually it is the reduced Compton wavelength, as shown in this article: 
 http://en.wikipedia.org/wiki/Thomson_scattering 
 Also, I have a physics textbook source: Nuclear and Particle Physics, Second Edition, B.R. Martin, pg 30.