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
Branches of physics This theory is currently under developmental stage. Optics is the study of light, and the instruments created to use or detect it (i.e. telescopes, spectrometers, etc.). Atomic physics, molecular physics, and optical physics are each individual sub-fields of AMO that study the physical properties of the atom, molecules, and light, respectively. The study of the physical properties of matter in a condensed phase. Particle physics studies the nature of particles, while nuclear physics studies the atomic nuclei. Cosmology studies how the universe came to be, and its eventual fate. It is studied by physicists and astrophysicists. To the interdisciplinary fields,