Extraction of the distribution function $h^{\perp}_{1T}$ from   experimental data
  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. 
Christopher Lefky, Alexei Prokudin
hep-ph