Université de Strasbourg

Boris Hippolyte


Hubert Curien Pluridisciplinary Institute (IPHC), University of Strasbourg

Boris Hippolyte, USIAS Fellow 2017

Boris Hippolyte joined the Department of Physics and Engineering at the University of Strasbourg as a faculty member in 2004, after having spent two years as a post-doctoral research and teaching associate at Yale University. He now specialises in subatomic physics on the fundamental structure of matter and is part of the Department of Subatomic Research at the Hubert Curien Pluridisciplinary Institute.

His research activities are dedicated to the studies of the “quark-gluon plasma”, which is the primordial state of the universe that prevailed for the first few microseconds after the Big Bang. The conditions of extreme energy densities needed for recreating this state of matter in the laboratory are nowadays obtained with ultra-relativistic collisions at large particle accelerators.

Boris Hippolyte is part of the ALICE (A Large Ion Collider Experiment) experiment located at the Large Hadron Collider of CERN (European Organization for Nuclear Research). He was involved in defining the experimental scientific programme and then coordinated several physics working groups. After being Alsace Fulbright fellow in 2008, he was an invited researcher at the Lawrence Berkeley National Laboratory (USA) and at CERN. His research focuses on the production of light flavour hadrons with collisions at very high energies, which constituted the main topic of his habilitation obtained in 2015. At the beginning of 2017, he was appointed Deputy Spokesperson of the ALICE Collaboration for a mandate of three years.

Project - Strange primordial matter

May 2017 - April 2018

Particle accelerators are amazing devices allowing us to not only probe infinitesimal scales but also reproduce, in the laboratory, the ambient conditions of the early Universe. With collisions of particles accelerated to speeds close to that of light, the amount of energy deposited in a volume the size of an atomic nucleus (~10-15 m) is such that the energy density is comparable to that of the Universe during the first microseconds after the Big Bang. In these extreme conditions, the primordial matter of the Universe is recreated for an instant (~10-23s) and forms a new thermodynamic state of matter called the Quark-Gluon Plasms (QGP).

Studying the properties and the evolution of the QGP sheds new light on the fundamental properties of the strong interaction responsible for the cohesion of matter. Thanks to data collected with the Relativistic Heavy Ion Collider (RHIC, at BNL near New York) and the Large Hadron Collider (LHC, at CERN, near Geneva), our understanding of QGP progressed tremendously revealing, for instance, novel properties of fluidity. Other very surprising results raised fundamental questions such as “What is smallest QGP droplet that can be created?” and “How can different types of collisions (involving protons, gold Au197 or lead Pb208 nuclei) be similar at very high energy?”.

This USIAS project aims at bridging nuclear and particle physics via the study of the hadronic final states, in order to understand how normal matter originates from QGP. It is based on systematic analyses of collisions obtained at LHC as a function of the number of charged particles produced (ranging from a small number in proton-proton collisions to several thousand for Pb-Pb). The main action will be the development of a thermal statistical model and its application to describe the production of hadrons with different quark flavours, in order to establish similarities and differences between lead-lead collisions - offering ideal conditions for obtaining QGP - and “elementary” proton-proton collisions, for which a sufficiently large number of created hadrons is necessary.


  • Boris Hippolyte's web page (CERN)
  • This project is carried out in memory of Professor Helmut Oeschler, and in collaboration with Professor Jean Cleymans, Emeritus Professor at the University of Cape Town, South Africa, Professor Krzysztof Redlich, University of Wroclaw, Poland and Dr Yves Schutz, Research Director at the Hubert Curien Pluridisciplinary Institute of Strasbourg, France.
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