Strong-Interaction matter coupled to electroweak probes and dark matter candidates
For decades, the Standard Model of particle physics has successfully
predicted the outcome of experiments probing the laws of nature on the
smallest distances. Its last missing ingredient, the Higgs particle,
was discovered at the Large Hadron Collider at CERN in 2012. A vast
experimental program is now underway to complete its description of weakly interacting particles called neutrinos.

For all its successes, the Standard Model does not provide an
explanation for the nature of dark matter, which is thought to account for a
quarter of the energy in the universe. This project, based on the
`lattice QCD' framework, will enable a more stringent test of the
Standard Model, contribute to narrowing down the list of
dark-matter candidate particles, and reduce uncertainties in neutrino
detection.

The strong interaction, which binds protons and neutrons together to
form atomic nuclei, is described by the sector of the Standard Model
called Quantum Chromodynamics (QCD). The complexity of the strong interaction
is often the limiting factor in testing the Standard Model and in
searching for new fundamental particles and forces. Strong-interaction
matter is also of tremendous intrinsic interest because it exhibits
many emerging phenomena such as spontaneous symmetry breaking,
quantum-relativistic bound states, and a high-temperature `quark-gluon
plasma' phase, to name a few. By replacing space and time by a
lattice, QCD becomes amenable to an ab initio treatment via
large-scale computer simulations.

The subproject of testing `sterile' neutrinos as dark-matter
constituents depends on understanding aspects of hot QCD matter, since
they would have been produced in the early, hot universe. This goal is
thus connected to present-day heavy-ion collision experiments, where
tiny droplets of hot QCD matter are produced in the laboratory.