Seminar of the department “Theory of Fundamental Interactions”

Date and Time: Thursday, 8 July 2021, at 3:00 PM

Venue: online seminar on Zoom, Bogoliubov Laboratory of Theoretical Physics

Seminar topic: “Transverse spin sum rule”

Speaker: Cédric Lorcé (Ecole Polytechnique, Palaiseau, France)

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.