Thermal radiation and entanglement in proton-proton collisions at energies available at the CERN Large Hadron Collider

The origin of the apparent thermalization in high-energy collisions is investigated using the data of the ATLAS and CMS Collaborations at the LHC. For this purpose, we analyze the transverse momentum distributions in the following proton-proton collision processes, all at s=13 TeV: (i) inclusive inelastic pp collisions; (ii) single- and double-diffractive Drell-Yan production pp→μ+μ-X; and (iii) Higgs boson production. We confirm the relation between the effective temperature and the hard scattering scale observed at lower energies, and find that it extends even to the Higgs boson production process. In addition we find that the thermal component disappears in diffractive events (even though many charged hadrons are still produced). We discuss the implications of our study for the mechanism of multiparticle production - in particular, we test the hypothesis about the link between quantum entanglement and thermalization in high-energy collisions.