LEGENDRE · Understanding the nature of the low energy excess in cryogenic detectors to discover light dark matter

Although numerous evidences from cosmology and astrophysics indicate the existence of Dark Matter (DM), which constitutes about 85% of the whole matter in the universe, its intrinsic nature is still today one of the major mysteries in physics. The lack of the discovery of the so-called Weakly Interacting Massive Particles is shifting the attention to additional, well-motivated, theoretical models that predict DM particles with lower masses. To test these, new extremely sensitive direct detection DM experiments have been developed, which are now starting to explore energies so low that were considered impossible to reach until just a couple of years ago. But these experiments are now observing unpredicted excesses of events, mostly incompatible with a DM signal, in the previously unexplored low energy region. And this irreducible background dramatically limits their sensitivity to new low-mass signals. In this project I propose a novel analysis strategy that will lead to the understanding of the nature of the low energy excess, providing invaluable information to the European and international experiments working on this field. I will also lead and coordinate the data taking campaign necessary for a positive outcome, which will employ world-leading sensitive cryogenic devices developed by the SuperCDMS collaboration, installed in the Cryogenic Underground Test at the world-class underground SNOLAB laboratory. The project will be completed in a leading research group, to which I will bring knowledge on how to efficiently operate a cryogenic detector as well as on how to run a dilution refrigerator. This work will extend my experience, show my research competencies and independence, enhancing the development of my career as a researcher.