Mainz 2022 – wissenschaftliches Programm

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HK: Fachverband Physik der Hadronen und Kerne

HK 12: Heavy-Ion Collisions and QCD Phases III

HK 12.1: Gruppenbericht

Montag, 28. März 2022, 16:00–16:30, HK-H1

Measurements of Heavy-flavour Baryon Production with ALICE at the LHC — •Jeremy Wilkinson for the ALICE collaboration — GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt

The measurement of charmed baryons in hadronic collision systems at the LHC has recently shown an enhancement of the charmed baryon-to-meson ratios (Λ_c⁺/D⁰ and Ξ_c/D⁰) with respect to previous measurements in e⁺e⁻ and e⁻p collisions, challenging previous assumptions about the universality of charm hadronisation processes between different collision systems. This in turn has a significant effect on the measured total charm cross section, where previously the relative contributions of charmed baryons had to be assumed based on results from leptonic collision experiments.

This talk will present the latest measurements performed by the ALICE Collaboration for charmed baryon production at mid-rapidity in pp and p–Pb collisions at the LHC. In particular, we highlight recent developments in analysis techniques using the XGBoost algorithm for machine learning selections, and the KFParticle package, which uses a Kalman filter to re-fit the decay tracks from baryon candidates and provide constraints to improve the mass resolution. These methods provide unprecedented experimental access to the low-p_T region for Λ_c⁺ to serve as a constraint on the charm fragmentation fractions. In addition, they can be used to give indirect access to the beauty sector through non-prompt Λ_c⁺, as well as previously inaccessible decays such as Ω_c⁰→ Ω⁻π⁺ and Ξ_c⁺→Ξ⁻π⁺π⁺.