First Simultaneous Global QCD Analysis of Dihadron Fragmentation Functions and Transversity Parton Distribution Functions

A new global QCD analysis by the JAM collaboration includes a comprehensive set of data in electron-positron annihilation, semi-inclusive deep-inelastic scattering, and proton-proton collisions, from which they extract simultaneously the transversity distributions of the nucleon and π⁺π^- dihadron fragmentation functions. Known theoretical constraints on transversity, namely, its small-x asymptotic behavior and the Soffer bound, are incorporated in the fit. It is shown that lattice-QCD results for the tensor charges can be successfully included in the analysis, resolving the previously reported incompatibility between the tensor charges extracted from dihadron production data and lattice QCD. Agreement is also find with results for the transversity and tensor charges obtained from measurements on single-hadron production. The work demonstrates for the first time the universal nature of all available information for the transversity distributions and the tensor charges of the nucleon.