Probe of soft-QCD in minimum bias events of pp collisions with the ATLAS at the LHC

TL;DR

This paper analyzes minimum-bias charged-particle distributions in proton-proton collisions at the LHC using ATLAS data across various energies, comparing results with Monte Carlo models to evaluate their accuracy in soft-QCD processes.

Contribution

It provides a comprehensive measurement of charged-particle distributions at multiple energies and evaluates the performance of different Monte Carlo tunings in modeling soft-QCD phenomena.

Findings

Monte Carlo models qualitatively agree with data but show significant discrepancies.

Charged-particle multiplicity depends on transverse momentum and pseudorapidity.

The study extends previous measurements with new energy and threshold data.

Abstract

The study of the minimum-bias charged-particle distributions is reviewed. The data are obtained using the ATLAS detector at the LHC in proton-proton collisions at the centre-of-mass energies from 0.9 to13 TeV. The particles are required to have an absolute pseudorapidity less than 2.5. For charged-particle distributions study two transverse momentum thresholds cases, greater than 100 MeV and 500 MeV were taken. The charged-particle multiplicity, its dependence on the transverse momentum and pseudorapidity, dependence of the average transverse momentum on the charged-particle multiplicity and the KNO-scaling study are presented. The measured distributions are compared with the predictions of various tunings of Monte Carlo generator, which implement different minimum-bias models.The Monte Carlo model predictions qualitatively describe the data well, but with some significant discrepancies. Measurements of minimum-bias events by the ALICE and CMS Collaborations are presented.