The Standard Model is the most advanced theoretical construct of the structure of matter. It provides a very precise description of the elementary components and their fundamental interactions. Despite countless successes, this theory is incomplete: dark matter is absent; neutrinos have no mass and therefore do not oscillate; particles behave too similarly to their antiparticles to explain the absence of antimatter in the Universe.

The structure of the Standard Model also raises profound questions. The most pressing is undoubtedly the stability of the scale of weak interactions, which is not guaranteed by the Higgs mechanism. Not to mention the absence of an arrow of time in strong nuclear interactions, even though this is permitted, and the origin of the triple replication of matter particles and their strong mass hierarchy.

There is no doubt that a New Physics exists beyond the Standard Model. Uncovering it is the subject of WP1. By exploring the highest energies with CERN's LHC collider and its successors, while at the same time taking detailed measurements of known phenomena at lower energies using various high-precision experiments.

Although they are the last remnants of the past life of stars, black holes and neutron stars offer a second life to their progenitors that is surprising and explosive, to say the least. Endowed with extreme gravitational fields, sometimes supernuclear densities, and surrounded by ultra-high intensity electromagnetic fields, these objects give rise to extreme eruptive episodes visible across the entire electromagnetic spectrum at cosmological distances. Some phenomena, such as the coalescence of compact objects, even generate strong gravitational wave emissions that are now detectable. They are also formidable natural laboratories where physical theories are pushed into unexplored regimes that are inaccessible on Earth.

The aim of the ENIGMASS+ federation is to gain a better understanding of these extreme phenomena through the development of instruments for telescopes on the ground (VIRGO, CTA, Rubin-LSST) and in space (SVOM, Athena), the scientific exploitation of their data, and the development of cutting-edge theory and numerical simulation codes.

The ΛCDM cosmological model describes current observations with remarkable accuracy, from the anisotropies of the cosmological diffuse background to the major structures of the Universe. However, this success is based on the assumption that dark energy (Λ) and dark matter (CDM), two components of unknown nature, dominate the Universe. The Enigmass+ project seeks to elucidate these major enigmas - dark energy, dark matter and the first instants of the universe - using a global approach that combines the development of new theories, the design of experiments and the exploitation of data.

In the field of astroparticle physics, Enigmass+ is contributing to research into dark matter by exploring direct and indirect detection methods. The programme focuses on the theoretical modelling of various dark matter candidates, while carrying out indirect searches at several wavelengths, such as observations of high-energy gamma rays or the analysis of stellar tidal currents in nearby galaxies observed optically. At the same time, Enigmass+ is developing advanced technologies for the direct detection of dark matter particles.

In cosmology, Enigmass+ is focusing on two main areas. On the one hand, it is exploring the primordial Universe, contributing to theoretical advances in quantum gravity, string theory and models of inflation and dark energy, as well as preparing for future experiments to observe the Universe.