Double-parton scattering mechanism for associated c c ¯ l+l- production in AA ultraperipheral collisions as a probe for the photon density inside the nucleus

We discuss the associated cc¯ and l+l- pairs production in ultraperipheral heavy-ion collisions at high energies. Such a channel provides a novel probe for double-parton scattering (DPS) at small x enabling one to probe the photon density inside the nucleus. We have derived an analog of the standard central pp pocket formula and studied the kinematical dependence of the effective cross section. Taking into account both elastic and nonelastic contributions, we have shown predictions for the DPS cc¯l+l- production cross section differential in charm quark rapidity and dilepton invariant mass and rapidity for LHC and a future collider.