학술논문

Dark Matter Search Results from the PICO-60 C$_3$F$_8$ Bubble Chamber
Document Type
Working Paper
Source
Phys. Rev. Lett. 118, 251301 (2017)
Subject
Astrophysics - Cosmology and Nongalactic Astrophysics
High Energy Physics - Experiment
Physics - Instrumentation and Detectors
Language
Abstract
New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C$_3$F$_8$ located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C$_3$F$_8$ exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than 1 event per month. A blind analysis of an efficiency-corrected 1167-kg-day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the WIMP-proton spin-dependent cross section at 3.4 $\times$ 10$^{-41}$ cm$^2$ for a 30-GeV$\thinspace$c$^{-2}$ WIMP, more than one order of magnitude improvement from previous PICO results.
Comment: 6 pages, 6 figures