Abstract: | Effects of polarization of hadrons and constituent quarks in Drell-Yan processes are considered; they are one of the most
efficient tools for investigation of the quark structure of hadrons. Special attention is paid to such important parton distribution
functions as the transversity and T-odd Sivers and Boer—Mulders functions whose study is necessary for understanding the effects connected with the nonzero transverse
component of the quark momentum. An original method for direct extraction of transversity and Boer—Mulders function in the
proton from the data on Drell—Yan processes, in which a maximum of one hadron in the initial state is transversely polarized,
is presented. This method possesses a number of important advantages. The method is applied both to Drell—Yan processes with
a valence antiquark (antiproton-proton and pion-proton collisions) and with a sea antiquark (proton-proton, proton-deuteron,
and deuteron-deuteron collisions). Theoretical estimates of asymmetries and cross sections for setups at RHIC (BNL, US), NICA
(JINR, Russia), COMPASS (CERN, Switzerland), PAX (GSI, Germany), and J-PARC (Japan) are presented for evaluation of the measurability
of transversity and T-odd distributions. These theoretical estimates are accompanied by calculations of statistical uncertainties
for measured asymmetries using the new Monte Carlo generator of Drell—Yan events. The duality of Drell—Yan processes and those
of production of J/Φ resonance is studied, and it may allow one to considerably reduce statistical uncertainties of parton distributions. Kinematical
conditions, for which this duality can be observed, are evaluated. |