We report on a global fit of neutral-current elastic (NCE) neutrino-scattering data and parity-violating electron-scattering (PVES) data with the goal of determining the strange quark contribution to the vector and axial form factors of the proton. Knowledge of the strangeness contribution to the axial form factor, $G_A^s(Q^2)$, at low $Q^2$ will reveal the strange quark contribution to the...
Unraveling the proton spin composition, comprising intrinsic spins and angular momenta of quarks and gluons, stands as one of the most fundamental and challenging questions in QCD. Much progress has been made since the first surprising result by the EMC experiment in the late 1980s. However, the helicity distributions of strange quarks and anti-quarks inside the proton are still not well...
In this talk, I will present the first extraction of TMD helicity distributions, by analyzing double spin asymmetry data from SIDIS.
we present a global analysis of Sivers function, transversity distribution functions and Collins fragmentation func-
tions within TMD factorization. This analysis encompasses the latest data sets from semi-inclusive deep inelastic scattering, Drell-
Yan, and W±/Z-boson production as recently reported by the COMPASS and STAR Collaborations. Upon integrating this new data
into our fitting,...
The study of the origins of transverse single-spin asymmetries has stimulated significant progress in the development of twist-3 formalism and transverse-momentum-dependent parton distribution functions (TMDs). Measurements of the azimuthal distribution of inclusive jets and identified hadrons within jets produced in transversely polarized hadronic interactions provide key insights into TMD...
Nuclear dependence of Single Transverse Spin Asymmetry (STSA) in pp and pA collisions is still a standing mystery. Recent results by PHENIX (A^(−1/3)) [1]
and STAR (A^0) [2] collaborations posses strikingly different nuclear scaling which suggest that the dominant underlying mechanism for STSA may vary with
the kinematics of the collision. In the forward regime, where the gluon saturation...