Initial and final state radiation Initial and final state radiation In particle physics, initial and final state radiation refers to certain kinds of radiative emissions that are not due to particle annihilation. It is important in experimental and theoretical studies of interactions at particle colliders. Particle accelerators and colliders produce collisions (interactions) of particles (like the electron or the proton). In the terminology of the quantum state, the colliding particles form the "Initial State". In the collision, particles can be annihilated or/and exchanged, producing possibly different sets of particles, the "Final States". The Initial and Final States of the interaction relate through the so-called scattering
Theoretical and experimental justification for the Schrödinger equation the clock in the observer frame. A wave-like picture of particles is thus consistent with special relativity. In fact, we now know that these relations can be succinctly written using special relativistic 4-vector notation: The relevant four-vectors are: The relations between the four-vectors are as follows: The phase of the wave is the relativistic invariant: The de Broglie hypothesis helped resolve outstanding issues in atomic physics. Classical physics was unable to explain the observed behaviour of electrons in atoms. Specifically, accelerating electrons emit electromagnetic radiation according to the Larmor formula. Electrons orbiting a nucleus should lose energy to radiation and