Speaker
Orin Harris
(Indiana University South Bend)
Description
The PICO Collaboration, formed from the merger of the Chicago-based COUPP and the Canadian-based PICASSO experiments, uses bubble chambers to search for dark matter. Bubble chambers are a unique dark matter detector technology. They provide very high $~10^{10}$ intrinsic electron recoil rejection, the ability to switch nuclear targets, acoustic rejection of alpha events, simple data acquisition, and low construction costs.
The PICO-2L bubble chamber exposed a heavily fluorinated C$_3$F$_8$ target fluid for 211.5 kg-days in the 2100 meter deep SNOLAB underground laboratory. In-situ measurements and measurements at the University of Montreal confirm the detector is sensitive to nuclear recoils with energies as low as 4 keV while maintaining excellent electron recoil and alpha rejection capabilities.
A background of nuclear recoil event candidates were observed during the run. The candidate events exhibit timing characteristics that are not consistent with the hypothesis of a uniform time distribution, and no evidence for a dark matter signal is claimed. Despite the background, these data provide the most sensitive direct detection constraints on WIMP-proton spin-dependent scattering to date.
World-leading results are also reported for the PICO-60 bubble chamber, a scale-up of the COUPP4 bubble chamber operated with $CF_3I$ target fluid at the SNOLAB underground laboratory.
| Oral or Poster Presentation | Oral |
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Primary author
Orin Harris
(Indiana University South Bend)
Co-author
PICO Collaboration
(PICO Collaboration)
