Relativistic spin sum rules and the role of the pivot
Cédric Lorcé
Abstract
Abstract Spin sum rules depend on the choice of a pivot, i.e. the point about which the angular momentum is defined, usually identified with the center of the nucleon. The latter is however not unique in a relativistic theory and has led to apparently contradictory results in the literature. Using the recently developed phase-space approach, we compute for the first time the contribution associated with the motion of the center of the nucleon, and we derive a general spin sum rule which reduces to established results after appropriate choices for the pivot and the spin component.
Topics & Concepts
PhysicsSpin (aerodynamics)Point (geometry)Angular momentumSum rule in quantum mechanicsCenter of mass (relativistic)Quantum mechanicsMotion (physics)Theoretical physicsMomentum (technical analysis)Center (category theory)Classical mechanicsRelativistic particleGeneral theoryRelativistic mechanicsAngular momentum operatorMathematicsRelativistic quantum chemistryWork (physics)Equations of motionCurrent (fluid)Quantum Chromodynamics and Particle InteractionsQuantum and Classical ElectrodynamicsParticle physics theoretical and experimental studies