Extraction of the distribution function $h^{\perp}_{1T}$ from experimental data

Understand

We attempt an extraction of the pretzelosity distribution ($h^{\perp}_{1T}$) from preliminary COMPASS, HERMES, and JLAB experimental data on $\sin(3\phi_h - \phi_S)$ asymmetry on proton, and effective deuteron and neutron targets.

• The resulting distributions, albeit with big errors, for the first time show tendency for up-quark pretzelosity to be positive and down-quark pretzelosity to be negative.
• A model relation of pretzelosity distribution and orbital angular momentum of quarks is used to estimate contributions of up and down quarks.