# Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at $\sqrt{s}$ = 13 TeV

## TL;DR

This study measures how the production of strange hadrons in proton-proton collisions at 13 TeV depends on event multiplicity, revealing a stronger increase with higher multiplicity and highlighting discrepancies with current QCD models.

## Contribution

It provides detailed measurements of strange hadron production as a function of multiplicity at 13 TeV, extending previous 7 TeV results and testing the predictive power of QCD models.

## Key findings

- Strange hadron yields increase faster than inclusive charged particles with multiplicity.
- The increase is more pronounced for hadrons with higher strangeness content.
- Current QCD models qualitatively reproduce some features but fail to match the data quantitatively.

## Abstract

The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ($\ |y\ | < 0.5$) are measured in proton-proton collisions at $\sqrt{s}$ = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of $\rm{K}^{0}_{S}$, $\Lambda$, $\Xi$, and $\Omega$ increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV.