Multiplicity and Underlying Event in ALICE: as measurements and as tools to probe QCD

TL;DR

This paper reviews ALICE measurements of charged-particle multiplicities and the Underlying Event at the LHC, highlighting their role in probing soft-QCD processes and constraining theoretical models.

Contribution

It provides recent experimental data and analysis on soft-QCD phenomena, offering insights to improve theoretical descriptions of non-perturbative particle production.

Findings

Charged-particle multiplicity measurements inform soft-QCD modeling.

Underlying Event studies help distinguish between different theoretical approaches.

Results highlight the need for refined models to match experimental data.

Abstract

With the high collision energies at the LHC, the contributions to particle production from hard-QCD processes increase, but it remains dominated by soft-QCD processes. Such processes challenge the theoretical models, since they are described by non-perturbative phenomenology. A selection of the most recent ALICE measurements of charged-particle multiplicities and the Underlying Event will be presented, focusing on model comparisons. A summary of the current understanding of soft-QCD processes will be discussed, evaluating possible ways to further constrain theory.