Abstract:

The review of the study of the minimum-bias (MB) charged-particle and sensitive to the underlying event (UE) distributions are presented. The data were obtained in proton–proton collisions at centre-of-mass energies from 900 GeV to 13 TeV using the ATLAS detector at the LHC. For charged-particle distributions study the two transverse momentum thresholds cases (greater than 100 MeV and 500 MeV) were used. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on the charged-particle multiplicity are presented. The UE distributions characterise the angular distribution of energy and particle flows with respect to the leading particle or Z-boson directions. The results are corrected for detector effects, presented as particle-level distributions. The measured distributions are compared with the predictions of various Monte Carlo generators tuning, which implement different MB or/and UE models.