An Etymological Dictionary of Astronomy and Astrophysics

The production of an → electron-positron pair in the → collision of two → gamma ray → photons (γγ → e⁺e^-). It is the → inverse process of → Dirac annihilation (e⁺e^-→ γγ). The Breit-Wheeler process is the simplest way by which pure → light can be potentially transformed into → matter. However, as of 2014, this process has never been observed in practice because of the difficulty in preparing colliding → gamma ray beams.

See also: Breit, G. & Wheeler, J. A. 1934, Collision of two light quanta. Phys. Rev. 46, 1087; → process.