Breit frame
In particle physics, the Breit frame (also known as infinite-momentum frame or IMF) is a frame of reference used to describe scattering experiments of the form Template:Tmath, that is experiments in which particle Template:Tmath scatters off particle Template:Tmath, possibly producing particles in the process.[1] The frame is defined so that the particle A has its momentum reversed in the scattering process.
Another way of understanding the Breit frame is to look at the elastic scattering Template:Tmath. The Breit frame is defined as the frame in which Template:Tmath. There are different occasions when Breit frame can be useful, e.g., in measuring the electromagnetic form factor of a hadron, Template:Tmath is the scattered hadron; while for deep inelastic scattering process, the elastically scattered parton should be considered as Template:Tmath. It is only in the latter case the Breit frame gets related to infinite-momentum frame.
It is named after the American physicist Gregory Breit.[2]