Light Dark Matter: New Directions for Theory and Detection

Dark matter is one of the biggest mysteries of the universe, yet its particle identity is unknown. This proposal focuses on light dark matter (LDM), with mass below a GeV. In Light-Dark, I will pursue two intrinsically complementary directions: (I) I will explore novel theoretical frameworks for LDM; and (II) I will develop new theoretical concepts to directly detect it in the laboratory. This pioneering theory work will lay the foundation for future experimental realizations and is crucial in the quest to unearth the identity of dark matter. I will carry out a comprehensive research program designed to tackle these challenges, and I believe that I am uniquely positioned to do so. Regarding (I), the wealth of annihilation channels, scattering processes, self-interactions, decay modes and mass splittings opens up a host of possible frameworks to set the LDM abundance, which I will explore. I have already proposed a paradigm-shifting idea in the form of the Strongly Interacting Massive Particle (SIMP) mechanism, which, along with other new ideas for LDM, will be thoroughly studied. Regarding (II), the study of novel target materials for LDM, sensitive sensors, collective excitations, detection philosophies and the interplay between them is crucially still in its infancy. I will explore new theoretical concepts and synergies in these experimental aspects, including the use of superconducting nanowires, microwave kinetic inductance devices, 2D layered materials, ferroelectrics and directionality, with prospects to detect LDM orders of magnitude beyond current abilities, down to the meV scale. Proof-of-principle has already been established for nanowires, where, using data from a tiny prototype device, I have already broken new ground in LDM parameter space. The innovative theoretical approaches presented here open up an exciting and groundbreaking ?eld of research. The proposed investigations are both timely and essential, paving the way towards a dark matter discovery.