Nuclear and Quark Matter Seminar 2023

Dates:
11.01. | 25.01.

Previous years: 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013

• 11 January 2023, 13:30 - Theory Seminar Room (BZ SB3 3.170a)
  
  Giuliano Giacalone - Heidelberg University, Heidelberg, Germany
  
  
  Abstract
  Modeling and understanding the quark-gluon plasma (QGP) formed in high-energy heavy-ion collisions requires some knowledge about the low-energy structure of the colliding nuclei. The success of the hydrodynamic model of the QGP enables us today to carefully scrutinize how such an input from low-energy nuclear physics affects the final outcome of heavy-ion collisions. Recently, experimental data from multiple collision systems has become available from the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider, and has permitted us to identify unambiguous signatures of the structural properties of nuclei in the experimental measurements.
  
  I review the status of the manifestations of so-called nuclear deformations, reflecting collective spatial correlations of nucleons in the nuclear wave functions, at high-energy colliders. I show that the expectations of low-energy nuclear physics appear to be consistently fulfilled by the observations at high energy, bringing confidence to our understanding of the collision processes. Hence, I discuss the prospects for theoretical and experimental work aimed at exploiting the structure of nuclei to further improve our understanding of the QGP, with an emphasis on collisions of light and medium-mass ions to be performed over the next two decades at the CERN LHC, and their synergy with the results of effective theories for nuclei rooted in QCD.
  Slides

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• 25 January 2023, 13:30 - KBW 2.28
  
  Jianhui Zhu - INFN, Padova, Italy
  
  
  Abstract
  The transition from quarks to hadrons is a fundamental process in nature that can be studied at colliders. Given their mass on the GeV scale, charm and beauty quarks are mainly produced in the hard scattering processes occurring in the early stages of the hadronic collisions. Compared to the hadronization, their production time is negligible, differently from light quarks. Thus, heavy quarks are used as markers to study the hadronization processes.
  
  Recent results at the LHC show a significant enhancement of charmed baryon-to-meson ratios in pp collisions with respect to e⁺e^- and e^-p collisions, assessing a possible non-universality of fragmentation functions among collision systems. These results suggest that the presence of surrounding colour charges may significantly influence the charm quark hadronization. Similar to what is expected in the quark-gluon plasma produced in ultra-relativistic heavy-ion collisions, heavy quarks can hadronize by combining with nearby lighter quarks in a process commonly called “coalescence” that modifies the hadro-chemistry expected in a pure fragmentation scenario.
  
  In this seminar, the most recent measurements with the ALICE experiment of charm baryon production (Λ_c⁺, Σ_c^0,+,++, Ξ_c^0,+, Ω_c⁰ in pp collisions, and Λ_c⁺ in p-Pb and Pb-Pb collisions) and an extension to the beauty sector via the measurement of Λ_c⁺ originating from beauty hadron decays will be presented. The comparison with theoretical model calculations will be discussed as well.
  Slides

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