First Simultaneous Extraction of Parton Distributions and Fragmentation Functions from a Global QCD Analysis

We perform the first global QCD analysis of inclusive and semi-inclusive deep-inelastic scattering and single-inclusive e+e- annihilation data, simultaneously fitting the parton distribution and fragmentation functions using the Monte Carlo nested sampling method. Without imposing SU(3) symmetry relations, we find the strange polarization to be very small, consistent with zero for both inclusive and semi-inclusive data, which provides a resolution to the strange quark polarization puzzle. We further quantify the impact of semi-inclusive deep-inelastic scattering data on the determination of the unpolarized strange and antistrange distributions.