First Extraction of Transverse Momentum Dependent Helicity Distributions
First Extraction of Transverse Momentum Dependent Helicity Distributions
We report on the first global analysis of transverse momentum dependent helicity distributions of the proton. The analysis is performed at next-to-leading order with the evolution factor at next-to-next-to-leading-logarithmic accuracy. Nonzero signals are determined for up and down quarks and their $k_T$-integrated polarization are consistent with analyses in collinear factorization, …