Double open charm meson production at the LHC: new single- and double-parton scattering mechanisms

We discuss D^0D^0 meson-meson pair production related to the recent LHCb experimental results obtained at sqrts = 7 TeV. We consider double-parton scattering (DPS) mechanisms of double cc̄ production and subsequent standard cc -> D^0D^0 scale-independent hadronization as well as double g and mixed gcc̄ production with gg -> D^0D^0 and gc -> D^0D^0 scale-dependent hadronization. The latter scenario with g -> D^0 fragmentation components results in a new single-parton scattering (SPS) mechanism of digluon production which is also taken here into account. Results of the numerical calculations are compared with the LHCb data for correlation observables in azimuthal angle phi_D^0D^0 between D^0 mesons, in dimeson invariant mass M_D^0D^0 and in transverse momentum of the meson from the D^0D^0 pair. The inclusion of the new mechanisms with g -> D^0 fragmentation leads to a larger cross sections and to slightly different shapes of the calculated correlation observables.