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Pair production often refers specifically to a photon creating an electron–positron pair near a nucleus. As energy must be conserved, for pair production to occur, the incoming energy of the photon must be above a threshold of at least the total rest mass energy of the two particles created. (As the electron is the lightest, hence, lowest ...
Pair production and annihilation: In the Stückelberg–Feynman interpretation, pair annihilation is the same process as pair production: Møller scattering: electron-electron scattering Bhabha scattering: electron-positron scattering Penguin diagram: a quark changes flavor via a W or Z loop Tadpole diagram: One loop diagram with one external leg
This expression can be derived by using a quantum mechanical symmetry between pair production and Bremsstrahlung. Z {\displaystyle Z} is the atomic number , α f i n e ≈ 1 / 137 {\displaystyle \alpha _{fine}\approx 1/137} the fine structure constant , ℏ {\displaystyle \hbar } the reduced Planck constant and c {\displaystyle c} the speed of ...
It is also referred to as the Sauter–Schwinger effect, Schwinger mechanism, or Schwinger pair production. It is a prediction of quantum electrodynamics (QED) in which electron – positron pairs are spontaneously created in the presence of an electric field, thereby causing the decay of the electric field.
To create an electron-positron pair, the total energy of the photons, in the rest frame, must be at least 2m e c 2 = 2 × 0.511 MeV = 1.022 MeV (m e is the mass of one electron and c is the speed of light in vacuum), an energy value that corresponds to soft gamma ray photons.
The Breit–Wheeler process is the creation of an electron–positron pair following the collision of two high-energy photons (gamma photons). The nonlinear Breit–Wheeler process or multiphoton Breit–Wheeler is the creation of an electron-positron pair from the decay of a high-energy photon (gamma photon) interacting with a strong electromagnetic field such as a laser.
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A gamma ray cross section is a measure of the probability that a gamma ray interacts with matter. The total cross section of gamma ray interactions is composed of several independent processes: photoelectric effect, Compton (incoherent) scattering, electron-positron pair production in the nucleus field and electron-positron pair production in the electron field (triplet production).