Single and pair $J\mathrm{/}\psi$ production in the Improved Color Evaporation Model using the Parton Reggeization Approach

In the article, we study single and pair $J\mathrm{/}\psi$ hadroproduction in the Improved Color Evaporation Model via the Parton Reggeization Approach. The last one is based on $k_T$-factorization of hard processes in multi-Regge kinematics, the Kimber-Martin-Ryskin-Watt model for unintegrated parton distribution functions, and the effective field theory of Reggezied gluons and quarks, suggested by L.N. Lipatov. We compare contributions from the single and double parton scattering mechanisms in the pair $J\mathrm{/}\psi$ production. The numerical calculations are realized using the Monte-Carlo event generator KaTie.