Including Cahn and Sivers effects into event generators

It is demonstrated that event generators LEPTO and PYTHIA can be modified to describe some azimuthal modulations. The comparisons of results obtained with modified LEPTO with existing data in the current fragmentation region of SIDIS are presented for Cahn and Sivers effects as well as the predictions for the target fragmentation region. The predictions for Sivers effect in the Drell–Yan process obtained with modified PYTHIA are also presented. The concept of hadronization function is discussed.