Simultaneous production of D and B mesons

We present results of our studies of double-parton scattering (DPS) effects in simultaneous production of heavy flavour mesons (charm and bottom). We discuss production of charm-bottom and bottom-bottom meson-meson pairs in proton-proton collisions at the LHC. The calculation of DPS mechanism is performed within factorized ansatz where each parton scattering is calculated within $k_T$-factorization approach. The hadronization is done with the help of fragmentation functions. For completeness we compare results for double- and single-parton scattering (SPS). The SPS components are also calculated in the $k_{T}$-factorization with the help of KaTie Monte Carlo generator. As in the case of double charm production also here the DPS dominates over the SPS, especially for small transverse momenta. We present several distributions and integrated cross sections with realistic cuts for simultaneous production of $D^0 B^+$ and $B^+ B^+$, suggesting future experimental studies at the LHC.