the principle that the total lepton number remains constant in any process involving elementary particles.
noun, Physics. 1. the principle that in any closed system subjected to no external forces, the mass is constant irrespective of its changes in form; the principle that matter cannot be created or destroyed. noun 1. the principle that the total mass of any isolated system is constant and is independent of any chemical and […]
noun, Physics. 1. the principle that the linear momentum of a system has constant magnitude and direction if the system is subjected to no external force.
- Conservation of momentum
noun 1. the principle that the total linear or angular momentum in any isolated system is constant, provided that no external force is applied conservation of momentum A conservation law stating that the total linear momentum of a closed system remains constant through time, regardless of other possible changes within the system.
- Conservation of parity
noun 1. the principle that the parity of the total wave function describing a system of elementary particles is conserved. In fact it is not conserved in weak interactions