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 12.2: Vortrag
Montag, 28. März 2022, 16:30–16:45, HK-H1
Reconstruction of Ξc+ → Ξ−π+π+ in proton-proton collisions at √s=13 TeV with the ALICE detector — •Carolina Reetz — Physikalisches Institut, Universität Heidelberg — GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt
Recent measurements of charmed-baryon production at midrapidity in pp and p-Pb collisions show a baryon-to-meson ratio significantly higher than the one in e+e− collisions, suggesting that the fragmentation of charm quarks into hadrons is not universal across different collision systems.
The reconstruction of the Ξc+ baryon decaying to Ξ−π+π+ with the ALICE detector is the subject of the studies presented in this contribution. The reconstruction of the complex decay topology is performed with the help of the KF Particle Package. It supports the reconstruction of full particle decay chains, exploiting the use of invariant mass and topological constrained fits and including the complete treatment of tracking and vertexing uncertainties. These features are of crucial importance in the selection of reconstructed candidates which is performed by applying machine learning techniques in the form of Boosted Decision Tree (BDT) models using XGBoost.
The application of these advantageous techniques is of utmost importance in the search for rare signals and allows to extract signal even in low pT-intervals where the signal-to-background ratio is rapidly decreasing. The cross section measurement together with the full treatment of the systematic uncertainties and the comparison to model calculations is reported.