Dark Matter Search Results from the PICO-2LC3F8Bubble Chamber

Abstract

New data are reported from the operation of a 2 liter C3F8 bubble chamber in the SNOLAB underground laboratory, with a total exposure of 211.5 kg days at four different energy thresholds below 10 keV. These data show that C3F8 provides excellent electron-recoil and alpha rejection capabilities at very low thresholds. The chamber exhibits an electron-recoil sensitivity of <3.5×10(-10) and an alpha rejection factor of >98.2%. These data also include the first observation of a dependence of acoustic signal on alpha energy. Twelve single 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. These data provide the most sensitive direct detection constraints on WIMP-proton spin-dependent scattering to date, with significant sensitivity at low WIMP masses for spin-independent WIMP-nucleon scattering.

Improved limits on dark matter annihilation in the Sun with the 79-string IceCube detector and implications for supersymmetry

“…Comparison of our limits with the latest constraints from Super-Kamiokande [2] and PICO [32,33]. Depending on the annihilation channel, IceCube provides the strongest limits above WIMP masses of ∼100-200 GeV.…”

“…Super-Kamiokande [2] is the most sensitive experiment at all lower masses. Limits from direct detection [32,33] are weaker, except in the case of DM with soft or suppressed annihilation spectra, in which case the PICO experiment [32,33] is the most constraining. Indirect DM searches by Antares [35] and Baksan [36] have set less stringent limits on the spin-dependent DM-proton scattering and are consequently not included in figure 6.…”

New Results from the Search for Low-Mass Weakly Interacting Massive Particles with the CDMS Low Ionization Threshold Experiment

“…In this case, the number densities of the two are also related, suggesting searches for particles with masses of a few GeV/c 2 . Hints of WIMP signals near detector thresholds [17][18][19][20][21], and an excess of gamma-ray emission from the Galactic Center [22], have also contributed to interest in the low-mass WIMP region [5,[23][24][25][26][27][28][29][30][31][32].…”

A minimal model for SU(N ) vector dark matter

“…We then investigate the phenomenological viability of the model numerically for N = 2, 3, and 4 by imposing the stability of the potential up to the Planck scale, requiring perturbativity of all couplings, and imposing the constraints from the LHC data. Furthermore we compute the dark matter relic density and impose constraints from the presently known abundance [12], as well as from the direct searches for dark matter [13][14][15].…”

“…The value of x f = m A /T f is determined by solving 14) where δ determines the deviation of the distribution from the equilibrium one, δ = Y /Y eq − 1, before the freeze out. The value of δ is expected to be O(1), and in the numerical analysis we choose δ = 1.…”