Ideas in Transverse Spin Physics

Abstract

Abstract. Three simple ideas about transverse spin observables are presented for the purpose of stimulating discussion. The manuscript is based on a presentation at the Transversity 2014 Workshop in Torre Chia, Sardinia, Italy on June 9-13, 2014 where approximately sixty experts on transverse spin physics had gathered to share recent results in an atmosphere of sun-drenched intensity.

Spin-Directed Momentum Transfers in SIDIS Baryon Production

“…The quantum entanglement produced by these final-state interactions can be isolated by the projection operator − Α Π of (1.9) The fact that the SIDIS process demonstrates TMD factorization [16] combined with the fact that SIDIS kinematics allows for a distinction between τ Α -odd dynamics occurring in the target nucleon from τ Α -odd effects in fragmentation. [17] The same kinematic restrictions occur for the production of baryons in the target fragmentation region of SIDIS as can be demonstrated by the three intersecting planes shown in Fig. 3 Since these momentum shifts do not evolve under TMD evolution [11,18], the data collected from spin asymmetries can be used to study the evolution of spin-averaged TMD's. Most of the familiar examples of quantum entanglement involve spin observables measured in widely separated kinematical regions.…”

“…A significant feature of spin-observables involving baryons is that polarization asymmetries and target spin asymmetries can be studied in tandem. Since these momentum shifts do not evolve under TMD evolution [11,18], the data collected from spin asymmetries can be used to study the evolution of spin-averaged TMD's. Most of the familiar examples of quantum entanglement involve spin observables measured in widely separated kinematical regions.…”