Scientific Program
Given the large infrastructures it often requires, particle physics has become increasingly over the last decades a more and more global enterprise, in which large projects and international collaborations rely on the pooling of multi-national human and financial resources over large periods of time. Though more recent, this very same trend is also shaping now projects in cosmology and particle astrophysics.
Even though not formally organized as such, the process by which the community discusses and defines the key topics and new ideas to explore in these fields is already global. The science is the same, as are its known unknowns, leading to common science drivers shared worldwide.
Building on these community-driven processes, several prioritization exercises at the country and/or regional level took place recently and led to strategic plans or roadmaps. CNRS Particles and Nuclei on one hand, with its national role and its 25 large laboratories and facilities often jointly operated by CNRS and universities, and on the other hand the University of Chicago and its partners in the area (Fermi National Accelerator Laboratory, as the largest particle physics lab in the US, and Argonne National Laboratory), are key-players in this field, are already collaborating on selected projects, and are strongly willing to further increase and deepen these collaborations.
The overall scope of the science to be undertaken is encapsulated in the following subset (non-exclusive) research clusters that have been identified:
Neutrino Physics and the DUNE Experiment
Neutrinos are among the most mysterious particles in the universe. Understanding their properties could shed light on some of the deepest questions in physics, including why the universe is made of matter. The IRL PPC is actively involved in the international Deep Underground Neutrino Experiment (DUNE)—a flagship U.S.-based project aiming to study neutrino oscillations, search for proton decay, and detect neutrinos from supernovae. This effort brings together a global community of scientists and institutions, including strong partnerships between CNRS laboratories, the University of Chicago, and Fermilab.
Advancing Particle Physics and Theory
Beyond neutrinos, the IRL PPC fosters collaboration across a broad range of topics in experimental and theoretical particle physics. This includes the study of the Higgs boson and its interactions, searches for new particles and forces, and the development of new theoretical models that go beyond the Standard Model.
The Chicago area hosts a vibrant theoretical physics community—spanning the Enrico Fermi Institute, the Kavli Institute for Cosmological Physics, Fermilab, and Argonne—whose work closely aligns with many IN2P3 research themes. Areas of shared interest include Higgs and electroweak physics, dark matter, collider phenomenology, lattice QCD, and quantum simulations.
While most experimental progress in these areas will come from CERN’s LHC, strong ties already exist: University of Chicago is involved in ATLAS, as are nine IN2P3 labs, while Fermilab plays a key role in CMS alongside several French groups. These connections offer ample opportunities for focused collaborations and visits, both in Chicago and in France.
Cosmology and Dark Matter
The IRL PPC fosters deep collaboration in the study of the dark universe, connecting experts in observational cosmology and dark matter across leading research institutions in France and the U.S. These collaborations span major international experiments, with contributions ranging from instrumentation and software to data analysis and theory.
In cosmology, joint efforts focus on large-scale surveys that aim to better understand dark energy and the evolution of the universe. Teams from both sides are involved in galaxy mapping and cosmic microwave background experiments, including current and next-generation observatories.
The search for dark matter is another central theme, with projects exploring a wide range of possible particle masses and detection strategies. This includes experiments operating in deep underground laboratories in both Europe and North America. Several promising initiatives have emerged from this shared effort, combining complementary expertise and infrastructure to push the frontiers of detection sensitivity.
R&D and Instrumentation for Accelerators and Detectors
Major projects like DUNE are pushing the frontiers of accelerator and detector technology. The new PIP-II accelerator, being built at Fermilab to power the high-intensity neutrino beam for DUNE, relies on cutting-edge superconducting radio-frequency (SRF) technology. French and U.S. teams are already working together on key components of this system, in what has become a highly successful and tightly integrated collaboration.
Looking beyond PIP-II, the IRL PPC aims to support further joint R&D in SRF technologies, including novel materials and cavity designs. Another promising direction is research into a future muon collider, a concept with renewed momentum in the U.S. and growing interest in France, thanks to its potential to serve both particle and neutrino physics.
Detector development is another area where shared expertise is already leading to innovation. IN2P3 and Chicago-area institutions are jointly involved in upgrades for the ATLAS experiment at the HL-LHC, as well as in light readout systems for DUNE. Several teams are also tackling the challenge of ultra-fast timing detectors—with resolutions in the range of 10–30 picoseconds—through complementary R&D efforts that could benefit from tighter coordination.
Astroparticle physics
Astroparticle physics connects the worlds of particle physics and astrophysics to explore the Universe’s most energetic and extreme phenomena. By studying cosmic messengers—such as high-energy photons, cosmic rays, neutrinos, and gravitational waves—researchers aim to better understand events like supernovae, black hole mergers, and the structure of space-time itself.
IN2P3 and institutions in the Chicago area have a long tradition of collaboration in this field, with shared involvement in landmark projects such as the Pierre Auger Observatory, cosmic ray and space-based missions, and gravitational wave detection through the LIGO and Virgo interferometers. These joint efforts have already advanced our understanding of high-energy astrophysical processes.
Looking ahead, the IRL PPC provides a framework to strengthen and coordinate future research in astroparticle physics. In particular, high-energy cosmic ray studies remain a promising area for deeper collaboration, building on existing ties and paving the way for new joint initiatives.