STRONG-DM

One of the most pressing question of modern physics is the nature of dark matter. Dark matter is a phenomenon of missing gravitating mass, observable on practically all astrophysical length scales - visible in the motion of stars in the galactic neighborhood as well as in the structure of the cosmological microwave background at the horizon of the observable Universe. The prevalent expectation is that dark matter consists of new particles, which themselves do not emit any light, but whose further microphysical structure is largely unknown. The research group STRONG-DM will address a to-date less studied particle candidate with a unique combination of experts. Much like neutrons - massive and electrically neutral particles of the atomic nucleus, made from quarks and gluons and bound through the strong force - dark matter can be a massive and electrically neutral bound state of a new strong force in a yet undiscovered sector of particles. This hypothesis has important consequences for the cosmic origin of dark matter and its production in collider experiments, for our astrophysical understanding of structure formation, as well as for the observation in so-called dark matter direct detection experiments. All these aspects will be investigated by a respective researcher who already brings broad expertise with her or him. Through a close collaboration, the topic will be studied from multiple angles at the same time, hence establishing a comprehensive picture of strongly interacting dark matter. To-date a major obstacle in any of the detailed phenomenological studies like the ones proposed above was the insufficient quantitative description of dark matter bound states. The team will overcome this obstacle by the addition of yet another expert who will utilize so-called lattice methods that were originally developed to study strong dynamics within the Standard Model of particle physics. It will hence, for the first time, be possible to investigate the possibility of strongly interacting dark matter starting from its fundamental structure to its detection within a synergetic research-infrastructure. We will therefore conclusively test the hypothesis of a so far relatively little studied - but very important - particle dark matter candidate.

One of the most pressing questions of modern physics concerns the nature of dark matter. Dark matter denotes the phenomenon of missing gravitating mass, observable on practically all astrophysical scales - from the motion of stars in our galactic neighborhood to the structure of the cosmic microwave background at the horizon of the observable Universe. The prevailing expectation that dark matter consists of new particles, which themselves do not emit light but whose microphysical properties were largely unknown, formed the starting point of the STRONG-DM project. The research group has focused on a to-date less studied candidate: a massive and electrically neutral bound state of a new strong force, analogous to neutrons that are bound states of quarks and gluons in the Standard Model. Over the course of the project, the cosmological implications of this hypothesis were investigated, production mechanisms in collider experiments were analyzed, the impact on astrophysical structure formation was assessed, and detection prospects in dark matter direct detection experiments were explored. Each of these aspects was addressed by an expert in the respective subfield, and through close collaboration a comprehensive picture of strongly interacting dark matter was established. A major obstacle in previous phenomenological studies had been the lack of a reliable quantitative description of such bound states. This challenge was successfully overcome by incorporating lattice methods originally developed to study strong dynamics in the Standard Model. This enabled, for the first time, a consistent investigation of strongly interacting dark matter from its fundamental structure to realistic detection scenarios within a unified research framework. STRONG-DM has thus provided a thorough test of the hypothesis of a so far little explored but theoretically well-motivated dark matter candidate, and has re-evaluated its viability across theory, phenomenology, and experimental prospects.