Bhabha scattering

Feynman diagrams
Annihilation
Scattering

In quantum electrodynamics, Bhabha scattering is the electron-positron scattering process:

There are two leading-order Feynman diagrams contributing to this interaction: an annihilation process and a scattering process. Bhabha scattering is named after the Indian physicist Homi J. Bhabha.

The Bhabha scattering rate is used as a luminosity monitor in electron-positron colliders.