Extraction of the Boer-Mulders Function from Unpolarized SIDIS Data

One avenue to study the 3D momentum-space tomography of hadrons is through high-energy electron-nucleon semi-inclusive deep-inelastic scattering (SIDIS) collisions, which are sensitive to parton intrinsic transverse momentum \textit{kT}. One finds that even in unpolarized SIDIS collisions, angular modulations, such as cos(2phi), occur in the cross section. The cos(2phi) dependence comes from two sources: a correlation between parton transverse spin and \textit{kT}, encoded in the twist-2 Boer-Mulders transverse momentum dependent (TMD) function that couples to the Collins TMD function; and a higher-twist (twist-4) so-called Cahn effect involving unpolarized TMD functions. In this work we study SIDIS data from HERMES, COMPASS, and CLAS in order to extract the Boer-Mulders function, considering also the contribution from the Cahn effect. We include not only cos(2phi) asymmetry data, but also HERMES and COMPASS multiplicity data as well as electron-positron annihilation data from BELLE, BaBar, and BESIII simultaneously in our analysis.