Speaker
Prof.
Bo-Qiang Ma
(Peking University)
Summary
It has been over 20 years for the proton spin ``crisis",i.e., the puzzle of where is the proton missing spin. Here I make a review on the explanation that the proton missing spin is due to the relativistic effect of quark transversal motions.
More generally, the transversal motions of quarks play a significant role in various physical quantities related to the proton spin structure, such as the helicity and transversity distributions, and the transverse-momentum-dependent (TMD) or three-dimensional parton distributions (3dPDFs). It is shown that the relativistic effect due to quark transversal motions plays a crucial role to understand the proton spin puzzle.
Primary author
Prof.
Bo-Qiang Ma
(Peking University)