Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
  • Editors' Suggestion

Dark Matter Search Results from the PICO−60 C3F8 Bubble Chamber

C. Amole et al. (PICO Collaboration)
Phys. Rev. Lett. 118, 251301 – Published 23 June 2017
PDFHTMLExport Citation
Abstract
Authors
See Also
Article Text
  • ACKNOWLEDGMENTS
    • References

    Abstract

    New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C3F8 located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO−60 C3F8 exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one 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 weakly interacting massive particle (WIMP)-proton spin-dependent cross section at 3.4×10−41  cm2 for a 30−GeV c−2 WIMP, more than 1 order of magnitude improvement from previous PICO results.

    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Figure
    • Received 9 March 2017

    DOI:https://doi.org/10.1103/PhysRevLett.118.251301

    © 2017 American Physical Society

    Physics Subject Headings (PhySH)

    1. Research Areas
    Cosmic ray & astroparticle detectorsParticle astrophysicsParticle dark matter
    Gravitation, Cosmology & Astrophysics

    Authors & Affiliations

    Click to Expand

    See Also

    Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure

    D. S. Akerib et al. (LUX Collaboration)
    Phys. Rev. Lett. 118, 251302 (2017)

    Article Text (Subscription Required)

    Click to Expand

    References (Subscription Required)

    Click to Expand
    Issue

    Vol. 118, Iss. 25 — 23 June 2017

    Reuse & Permissions
    Access Options
    CHORUS

    Article Available via CHORUS

    Download Accepted Manuscript
    Author publication services for translation and copyediting assistance advertisement

    Authorization Required

    Log In
    Other Options
    ×

    Images

    • Figure 1
      Figure 1

      Spatial distribution of single-bubble events in the WIMP search data. Z is the reconstructed vertical position of the bubble, and R2/Rjar is the distance from the center axis squared, normalized by the nominal jar radius (145 mm). The fiducial cut is represented by the dashed line. The red squares are the 106 single bulk bubbles passing all cuts prior to acoustic unblinding and the gray dots are all rejected single-bubble events.

      Reuse & Permissions
    • Figure 2
      Figure 2

      Top: AP distributions for AmBe and Cf252 neutron calibration data (black) and WIMP search data (red) at a 3.3 keV threshold. Bottom: AP and NN score for the same data set. The acceptance region for nuclear recoil candidates, defined before WIMP search acoustic data unmasking using neutron calibration data, is displayed with dashed lines and reveals no candidate events in the WIMP search data. Alphas from the Rn222 decay chain can be identified by their time signature and populate the two peaks in the WIMP search data at a high AP. Higher energy alphas from Po214 are producing larger acoustic signals.

      Reuse & Permissions
    • Figure 3
      Figure 3

      The 90% C.L. on the SD WIMP-proton cross section from PICO−60 C3F8 plotted in thick blue, along with limits from PICO−60 CF3I (thick red) [10], PICO-2L (thick purple) [9], PICASSO (green band) [14], SIMPLE (orange) [15], PandaX-II (cyan) [29], IceCube (dashed and dotted pink) [30], and SuperK (dashed and dotted black) [31, 32]. The indirect limits from IceCube and SuperK assume annihilation to τ leptons (dashed) and b quarks (dotted). The purple region represents parameter space of the constrained minimal supersymmetric model of Ref. [33]. Additional limits, not shown for clarity, are set by LUX [34] and XENON100 [35] (comparable to PandaX-II) and by ANTARES [36, 37] (comparable to IceCube).

      Reuse & Permissions
    • Figure 4
      Figure 4

      The 90% C.L. on the SI WIMP-nucleon cross section from PICO−60 C3F8 plotted in thick blue, along with limits from PICO−60 CF3I (thick red) [10], PICO-2L (thick purple) [9], LUX (yellow) [38], PandaX-II (cyan) [39], CRESST-II (magenta) [40], and CDMS-lite (black) [41]. While we choose to highlight this result, LUX sets the strongest limits on WIMP masses greater than 6  GeV/c2. Additional limits, not shown for clarity, are set by PICASSO [14], XENON100 [35], DarkSide-50 [42], SuperCDMS [43], CDMS-II [44], and Edelweiss-III [45].

      Reuse & Permissions
    • Figure 5
      Figure 5

      PICO-60 constraints (blue) on the effective spin-dependent WIMP-proton and WIMP-neutron couplings, ap and an, for a 50  GeV/c2 WIMP mass. Parameter space outside of the band is excluded. Also shown are results from PANDAX-II (cyan) [29], LUX (yellow) [34], PICO-2L (purple) [9], and PICO−60 C3FI (red) [10].

      Reuse & Permissions
    • Figure 6
      Figure 6

      Exclusion limits at the 95% C.L. in the mDM−mmed plane. PICO-60 constraints (thick blue) are compared against collider constraints from CMS for an axial-vector mediator using the monojet and mono-V (red) [50] and monophoton (orange) [51] channels. The shaded regions signify excluded parameter space for the chosen model. A similar analysis by ATLAS can be found in Ref. [52].

      Reuse & Permissions
    ×

    Sign up to receive regular email alerts from Physical Review Letters

    Log In

    Cancel
    ×

    Search

    Article Lookup

    Paste a citation or DOI
    Enter a citation
    ×