Probing strangeness production in pp collisions at 13 TeV through multi-differential measurements with ALICE at the LHC

Adrian Fereydon Nassirpour (Lund University)

Significant strangeness enhancement and radial flow have been observed in high-multiplicity pp collisions at LHC. The origin of these effects is still under debate, but most likely indicate that proton-proton collisions cannot be seen as incoherent sums of parton-parton collisions, an idea that has been central in most proton-proton generators, for example PYTHIA.To accommodate the new ALICE results, different models introduce final state effects of very different phenomenological origin. Multi-differential strange particle production studies can be used as key tool to discriminate among different final state effects at play

In this contribution, new and more differential measurements are presented, making use of event-shape techniques and two-particle correlation functions to study final-state topologies:

    the transverse spherocity, which aims to classify events based on the azimuthal topology.
    the self-normalized Underlying Event (UE) activity, 𝑅T, which allows the UE to be significantly suppressed or enhanced.
    two-particle Ξ-hadron correlations, to study associated strangeness production.

Using observables that control the hard-to-soft ratio and the UE, one gains novel insights into the mechanism responsible for the QGP-like effects in small systems. The results will be presented for a large variety of strange and non-strange hadrons and resonances ($\pi$, K, $\mathrm{K}_0^*$, p, $\phi$, and $\Xi$) and will be compared to calculations using both PYTHIA 8 and EPOS LHC event generators.

The colloquium will be streamed but not recorded.

Zoom link: https://uni-frankfurt.zoom.us/j/2848286010?pwd=VmtCY1RCc1hpVStKd0RibFBpc1IzZz09

Meeting ID: 284 828 6010
Password: 068695