Double-photon exclusive processes with heavy-quark–heavy-antiquark pairs in high-energy Pb-Pb collisions at energies available at the CERN Large Hadron Collider

Abstract

The cross section for exclusive heavy-quark and heavy-antiquark pair ($Q\mathrm{Q\ifmmode \bar{}\else \={}\fi{}}$) production in peripheral ultrarelativistic heavy-ion collisions is calculated at an energy available at the CERN Large Hadron Collider, i.e., $\sqrt{{s}_{\mathit{NN}}}$ = 5.5 TeV. Here we consider only processes with photon-photon interactions and omit diffractive contributions. We present results in the impact parameter equivalent photon approximation and compare some of them with results obtained by exact calculations of the Feynman diagrams in the momentum space. We include $Q\mathrm{Q\ifmmode \bar{}\else \={}\fi{}}$, $Q\mathrm{Q\ifmmode \bar{}\else \={}\fi{}}g$, and $Q\mathrm{Q\ifmmode \bar{}\else \={}\fi{}}q\mathrm{q\ifmmode \bar{}\else \={}\fi{}}$ final states as well as photon single-resolved components. Realistic charge densities in nuclei were taken in the calculation. The different components give contributions of the same order of magnitude to the nuclear cross section. The cross sections found here are smaller than those for the diffractive photon-Pomeron mechanism and larger than the diffractive Pomeron-Pomeron discussed in the literature.