1. Particle Physics Seminar

    "Dark Matter Search Results from PICO-2L"

    Presented by Chanpreet Amole, Queen's University, SNOLAB

    Thursday, April 7, 2016, 10 am
    Small Seminar Room, Bldg. 510

    Hosted by: Xin Qian

    New data are reported from a second run of the 2-liter PICO-2L C3F8 bubble chamber with a total exposure of 129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data show that measures taken to control particulate con-tamination in the superheated fluid resulted in the absence of the anomalous back-ground events observed in the first run of this bubble chamber. One single nuclear-recoil event was observed in the data, consistent both with the predicted background rate from neutrons and with the observed rate of unambiguous multiple-bubble neutron scattering events. The chamber exhibits the same excellent electron-recoil and alpha decay rejection as was previously reported. These data provide the most stringent direct detection constraints on WIMP- proton spin-dependent scattering to date for WIMP masses < 50 GeV/c2.