Measurements of charged-particle distributions at $\sqrt{s}=8$ and $13$ TeV with the ATLAS detector

Inclusive charged-particle measurements at hadron colliders probe the low-energy non-perturbative region of QCD. The ATLAS collaboration has measured the primary-charged-particle multiplicity and its dependence on transverse momentum and pseudorapidity in special data sets with low LHC proton--proton beam currents, recorded at centre-of-mass energies of 8~TeV and 13~TeV. The new precise measurements at 8~TeV cover a wide spectrum of distributions using charged-particle selections with minimum transverse momentum of both 100~MeV and 500~MeV and in various phase-space regions of low and high charged-particle multiplicities. Two measurements at 13~TeV present the first detailed studies with a minimum transverse momentum of 500~MeV and 100~MeV. The measurements are compared with predictions of various MC generators and are found to provide strong constraints on these.