Yohan Ricci
Queen's University
Dark Matter (DM) is thought to make up 84.5% of the matter content of the universe. It is a key ingredient of the standard model of cosmology (CDM) and could provide a window to new theories beyond the standard model of particle physics. The Super Cryogenic Dark Matter Search (SuperCDMS) experiment is currently operating 15 new and improved germanium detectors at the Soudan Underground Laboratory in Minnesota, USA. Those detectors are used to search for Weakly Intereating Massive Particules (WIMPs) with masses in the range of 10 GeV to 10 TeV with a regular' high threshold analysis. They were also recently used to obtain two important results in the search for low-mass WIMPs with dedicated low threshold analyses. The seminar will focus on CDMS results and in particular the two aforementioned low-mass WIMP results.
I will present the results and prospects of a special operational mode with a very low ionization threshold called CDMSlite (CDMS low ionization threshold experiment). For this innovative experiment, we operated a single detector with a higher voltage than usual and we were able to measure a much smaller ionization signal than the regular experiment at the expense of background rejection capabilities. Thanks to this feature, we obtained the lowest threshold in a germanium detector experiment allowing us to explore new WIMP parameter space below 6 GeV. A longer run in this mode started in February 2014 and will continue for several months.
I will also present a special low threshold analysis (at regular voltage) which used both the phonon and ionization information of the new detectors to perform an efficient background rejection. The results of this analysis are in tension with the WIMP interpretation of excess events in several experiments.
