Breit–Wheeler process

Breit–Wheeler process or Breit–Wheeler pair production is the simplest mechanism by which pure light can be potentially transformed into matter.^[1] The process can take the form of γγ′ → e⁺e⁻, that is the emission of positron–electron pairs off a probe photon propagating through a polarized short-pulsed electromagnetic field (for example, laser).^[2]

The process was described by Gregory Breit and John A. Wheeler in 1934 in Physical Review.^[3] Although the process is one of the manifestations of the mass–energy equivalence, as of 2014, it has never been observed in practice because of the difficulty in preparing colliding gamma ray beams. However, in 1997, researchers at the Stanford Linear Accelerator Centre were able to conduct the so-called multi-photon Breit–Wheeler process using electrons to first create high-energy photons, which then underwent multiple collisions to produce electrons and positrons, all within same chamber.^[4] In 2014 a model of a photon–photon collider was proposed, where Monte Carlo simulations suggest that it is capable of producing of the order of 10⁵ Breit–Wheeler pairs in a single shot.^[1]

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