Speaker
Description
One of the remaining puzzles in heavy-ion physics is that observables thought to be signatures of a Quark-Gluon Plasma - such as flow and strangeness enhancement - are not only observed in heavy-ion collisions, but also in high-multiplicity proton-proton and proton-nucleus collisions. Various phenomenological models are being developed to try to understand this. These include both extensions of QCD inspired models with new features, such as rope hadronisation in the Angantyr extension of PYTHIA, or adding new phases, such as in the core-corona model (i.e. a QGP core surrounded by a QCD like corona) used for example in EPOS. These models are fundamentally different from each other, and therefore more experimental input is crucial to be able to distinguish between them. One approach is to use angular correlations between different hadronic species, and in particular strange hadrons. In this presentation, various correlation measurements in pp collisions from ALICE will be presented, along with phenomenological predictions.
The observables presented here are $\Xi-\rm K$ and $\Xi-\pi$ correlations to probe strangeness production, $\pi-\pi$, $\rm K-K$, $\rm p-p$, $\rm p-\Lambda$, and $\Lambda-\Lambda$ correlations to probe meson and baryon production, and $\pi,\rm K$, and p balance functions - i.e. the difference between same-sign and opposite-sign correlations - to probe charge-dependent effects in particle production. These measurements are important to gain a better understanding of the hadron production mechanism in small systems.
