Kinematical correlations of dielectrons from semileptonic decays of heavy mesons and Drell-Yan processes at BNL RHIC

We discuss kinematical correlations between charged leptons from semileptonic decays of open charm/bottom leptons produced in the Drell-Yan mechanism as well as some other mechanisms not included so far in the literature in proton-proton scattering at Brookhaven National Laboratory (BNL) Relativistic Heavy Ion Collider (RHIC). The distributions of charm and bottom quarks/antiquarks are calculated in the framework of the k(t)-factorization approach. For this calculation we use different unintegrated parton distributions from the literature. The hadronization of heavy quarks is done with the help of well-known fragmentation functions. Uncertainties of our predictions related to heavy quark masses, factorization, and renormalization scales as well as due to the choice of fragmentation model are also discussed. We use semileptonic decay functions found by fitting recent semileptonic data obtained by the CLEO and BABAR collaborations. The Drell-Yan processes were calculated including transverse momenta of quarks and antiquarks, using the Kwiecinski parton distributions. We have also taken into consideration reactions initiated by purely QED gamma*gamma* fusion in elastic and inelastic pp collisions as well as a recently proposed diffractive mechanism of exclusive charm-anticharm production. The contribution of the latter mechanism is rather small. We get a good description of the dilepton invariant mass spectrum measured recently by the PHENIX Collaboration and present predictions for the dilepton pair transverse momentum distribution as well as the distribution in the azimuthal angle between electron and positron.