Analysis of the cos(2φ) and cos(φ) modulations in semi-inclusive deep-inelastic scattering*

The 3D momentum-space tomography of hadrons can be studied through azimuthal modulations that arise in the cross-section of high-energy particle collisions. Lepton-nucleon semi-inclusive deep-inelastic scattering (SIDIS) is of particular interest due to the sensitivity resulting from the parton intrinsic transverse momentum k_T. The cos(2φ) modulation has two sources: a correlation between parton transverse spin and k_T, encoded in the twist-2 Boer-Mulders Transverse Momentum Dependent (TMD) function, and a higher-twist (twist-4) so-called Cahn effect involving unpolarized TMD functions. In this work, we study SIDIS data from the HERMES, COMPASS, and CLAS collaborations in order to extract the Boer-Mulders function while considering contributions from the Cahn effect. Also, theory calculations are implemented for the cos(φ) modulation, using results from the cos(2φ) analysis, to help further validate the non-perturbative quantities extracted from the latter analysis.