Thèse Caractérisation de l'Hadronisation du Charme avec des Baryons Auprès de l'Expérience Lhcb H/F - Doctorat.Gouv.Fr

Établissement : Institut Polytechnique de Paris École polytechnique École doctorale : Ecole Doctorale de l'Institut Polytechnique de Paris Laboratoire de recherche : LLR - Laboratoire LEPRINCE-RINGUET Direction de la thèse : Frédéric FLEURET ORCID 000000022430782X Début de la thèse : 2026-10-01 Date limite de candidature : 2026-06-01T23:59:59 The PhD project focuses on studying the hadronization process in Quantum Chromodynamics using the unique fixed-target data collected by the LHCb experiment.These proton-nucleus and lead-nucleus collisions, recorded by LHCb at around 100 GeV, provide access to a special kinematic region, allowing detailed investigation of the transition between fragmentation and coalescence mechanisms involved in the hadronisation of charm quarks.

The candidate will perform the first measurement of open-charm baryon production in these fixed-target collisions using full LHC Run 3 data, offering crucial constraints on hadronization models relevant to both collider and heavy-ion environments.

In parallel, the student will have the opportunity to contribute to the development of a new tracking detector for the LHCb Upgrade II, based on CMOS MAPS technology. This detector will significantly enhance tracking performance, especially in high-multiplicity conditions, and the candidate will take part in its design, prototyping, and optimization.

This combined physics-analysis and detector-development work will position the student at the forefront of next-generation heavy-ion physics and LHCb instrumentation The fixed-target configuration of the LHCb experiment offers a unique opportunity at the LHC to explore an unprecedented region of phase space. This innovative setup was tested during LHC Run 2 with pioneering data-taking periods. Despite their limited statistics, these datasets allowed the extraction of the first physics results, demonstrating the feasibility of a dedicated program focused on studying charmed-hadron production. These studies were carried out at the Laboratoire Leprince Ringuet.

During the long LHC shutdown (2018-2022), the fixed-target system was upgraded to significantly increase the interaction rate between the LHC beam and the target (a factor of 100). Initial tests of this new fixed-target configuration, performed in November 2022, validated the successful operation of the upgrade.

After the year 2023, which was dedicated to commissioning the LHCb detector, 2024 marks the ramp-up of proton-proton and proton-fixed-target data taking, paving the way for precise studies of Quantum Chromodynamics (QCD) in an unprecedented configuration.

Master 2 en physique des particules