Monte-Carlo simulation of lepton pairs production in 'pp-bar → e~+e~- + X' events at PANDA experiment

摘要

Electron-positron pairs production via the quark-antiquark annihilation process in collisions of antiproton beam having E_(eam) = 15 GeV with the proton target in PANDA experiment is modeled by using the PYTHIA6.4 Monte-Carlo event generator and PandaRoot framework. The considered quark level subprocess pass through the production of virtual photon which converts into the lepton pair (qq-bar → γ~* → e~+e~-). The spectrum of the final state leptons in this process of quark-antiquark annihilation obviously depends on the form of parton distributions inside colliding protons and may provide an interesting information about the quark dynamics inside the hadron. The measurement of the total transverse momentum of a lepton pair as a whole system may give an important information about the intrinsic transverse momentum k_T that appears due to the Fermi motion of quarks inside the nucleon. In the article the distributions of different kinematical variables of final state electrons/positrons are presented. The influence of the detector environment on the presence of fake leptons is demonstrated. The signal leptons registration efficiency is calculated. The background contribution is also discussed.