Dirac equation in the algebra of physical space Dirac equation in the algebra of physical space The Dirac equation, as the relativistic equation that describes spin 1/2 particles in quantum mechanics, can be written in terms of the Algebra of physical space (APS), which is a case of a Clifford algebra or geometric algebra that is based on the use of paravectors. The Dirac equation in APS, including the electromagnetic interaction, reads Another form of the Dirac equation in terms of the Space time algebra was given earlier by David Hestenes. In general, the Dirac equation in the formalism of geometric algebra has the advantage of providing a
Interaction point whole region around the interaction point (the experimental hall) is called an interaction region. Particle colliders such as LEP, HERA, RHIC, Tevatron and LHC can host several interaction regions and therefore several experiments taking advantage of the same beam. Interaction point In particle physics, an interaction point (IP) is the place where particles collide in an accelerator experiment. The "nominal" interaction point is the design position, which may differ from the "real" or "physics" interaction point, where the particles actually collide. A related, but distinct, concept is the "primary vertex": the reconstructed location of an individual particle collision. For fixed