Many astrophysical observations suggest that ordinary matter- which makes up galaxies, the Earth, us- only accounts for less than 5% of the Universe. Most of the matter in the universe, which is non-luminous and thus referred to as dark matter (DM), is unknown. Unveiling the nature of DM is one of the most fundamental open questions in Physics today.
The search for WIMPs (weakly interacting massive particles), one of the most favoured class of DM candidates, with predicted mass in the range of 1 to 10000 proton masses, is among the highest priorities of astroparticle physics for the next decade. An increasingly important area of the field is searches for DM candidates beyond the WIMP paradigm, most notably at lower masses. This complementary region of the parameter space is extraordinarily challenging to address experimentally, due to the low detection thresholds required, the difficult background mitigation and challenging detector calibration.
Silicon detectors are one of the most promising techniques to overcome the experimental challenges. The DarkSide experiment aims to discover DM by observing its interactions with ordinary matter in an ultra-sensitive liquid argon detector. DarkSide's major technological advance is to employ a novel silicon-based light detector system (silicon photo-multiplier, SiPMs), specifically developed for the experiment, to observe tiny signals that may be created in the argon following a DM particle interaction. While these devices enable a projected 100x increase in sensitivity over current results for WIMP DM candidates, the full range of potential applications is yet unexplored.
My proposed research leverages the unique opportunities of the novel DarkSide SiPM and aims at further developing this technology, with potential application in future particle astrophysics experiments and industry. The main goal of the programme is to perform new searches for light DM interactions in the SiPMs themselves, a novel approach profiting from the large mass of ultra-radio-pure silicon deployed in the DarkSide detector. This will significantly broaden discovery reach, to a yet-uncovered and compelling mass range.
