Soft QCD results from ALICE

TL;DR

This paper presents new soft QCD measurements from ALICE at the LHC, analyzing underlying event characteristics in p-Pb collisions and their correlation with forward energy, providing insights into soft interactions and hadron production.

Contribution

It introduces the first underlying event analysis in p-Pb collisions at the LHC and explores correlations with forward energy to distinguish initial and final-state effects.

Findings

UE measurements in p-Pb collisions show similarities with pp collisions.

UE at midrapidity correlates with forward energy measured by ZDC.

Multi-differential studies help disentangle effects on strange hadron production.

Abstract

High-energy hadronic collisions are dominated by soft interactions with low momentum transfers. The description of these processes typically relies on phenomenological models. The soft QCD measurements, such as characterisation of the underlying event (UE) and study of light flavored hadrons, provide important constraints on the model parameters. They also provide additional insights into the recent measurements at the LHC where features normally attributed to QGP formation in Pb-Pb collisions have been observed even in pp and p-Pb collisions. Here, we present an analysis based on UE measurements applied to p-Pb collisions for the first time at the LHC to test the similarities between pp and p-Pb collisions. Furthermore, it is shown that the UE at midrapidity is correlated with the energy measured at forward rapidity by ALICE zero degree calorimeters (ZDC). Using ZDC, a multi-differential study is shown to disentangle initial and final-state effects on strange hadron production in pp collisions.