Results from the Final Exposure of the CDMS II Experiment

We report results from a blind analysis of the final data taken with the Cryogenic Dark Matter Search experiment (CDMS II) at the Soudan Underground Laboratory, Minnesota, USA. A total raw exposure of 612 kg-days was analyzed for this work. We observed two events in the signal region; based on our background estimate, the probability of observing two or more background events is 23%. These data set an upper limit on the Weakly Interacting Massive Particle (WIMP)-nucleon elastic-scattering spin-independent cross-section of 7.0x10^{-44} cm^2 for a WIMP of mass 70 GeV/c^2 at the 90% confidence level. Combining this result with all previous CDMS II data gives an upper limit on the WIMP-nucleon spin-independent cross-section of 3.8x10^{-44} cm^2 for a WIMP of mass 70 GeV/c^2. We also exclude new parameter space in recently proposed inelastic dark matter models.Comment: 6 pages, 5 figure

Search for inelastic dark matter with the CDMS II experiment

Results are presented from a reanalysis of the entire five-tower data set acquired with the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory, with an exposure of 969 kg-days. The analysis window was extended to a recoil energy of 150 keV, and an improved surface-event background-rejection cut was defined to increase the sensitivity of the experiment to the inelastic dark matter (iDM) model. Three dark matter candidates were found between 25 keV and 150 keV. The probability to observe three or more background events in this energy range is 11%. Because of the occurrence of these events, the constraints on the iDM parameter space are slightly less stringent than those from our previous analysis, which used an energy window of 10–100 keV. © 2011 American Physical Societ

The Indirect Search for Dark Matter with IceCube

We revisit the prospects for IceCube and similar kilometer-scale telescopes to detect neutrinos produced by the annihilation of weakly interacting massive dark matter particles (WIMPs) in the Sun. We emphasize that the astrophysics of the problem is understood; models can be observed or, alternatively, ruled out. In searching for a WIMP with spin-independent interactions with ordinary matter, IceCube is only competitive with direct detection experiments if the WIMP mass is sufficiently large. For spin-dependent interactions IceCube already has improved the best limits on spin-dependent WIMP cross sections by two orders of magnitude. This is largely due to the fact that models with significant spin-dependent couplings to protons are the least constrained and, at the same time, the most promising because of the efficient capture of WIMPs in the Sun. We identify models where dark matter particles are beyond the reach of any planned direct detection experiments while being within reach of neutrino telescopes. In summary, we find that, even when contemplating recent direct detection results, neutrino telescopes have the opportunity to play an important as well as complementary role in the search for particle dark matter.Comment: 17 pages, 10 figures, published in the New Journal of Physics 11 105019 http://www.iop.org/EJ/abstract/1367-2630/11/10/105019, new version submitted to correct Abstract in origina

Puzzles of Dark Matter - More Light on Dark Atoms?

Positive results of dark matter searches in experiments DAMA/NaI and DAMA/LIBRA confronted with results of other groups can imply nontrivial particle physics solutions for cosmological dark matter. Stable particles with charge -2, bound with primordial helium in O-helium "atoms" (OHe), represent a specific nuclear-interacting form of dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct methods of underground Dark matter detection using its nuclear recoil. However, low energy binding of OHe with sodium nuclei can lead to annual variations of energy release from OHe radiative capture in the interval of energy 2-4 keV in DAMA/NaI and DAMA/LIBRA experiments. At nuclear parameters, reproducing DAMA results, the energy release predicted for detectors with chemical content other than NaI differ in the most cases from the one in DAMA detector. Moreover there is no bound systems of OHe with light and heavy nuclei, so that there is no radiative capture of OHe in detectors with xenon or helium content. Due to dipole Coulomb barrier, transitions to more energetic levels of Na+OHe system with much higher energy release are suppressed in the correspondence with the results of DAMA experiments. The proposed explanation inevitably leads to prediction of abundance of anomalous Na, corresponding to the signal, observed by DAMA.Comment: Contribution to Proceedings of XIII Bled Workshop "What Comes beyond the Standard Model?

Dark Matter in the MSSM

We have recently examined a large number of points in the parameter space of the phenomenological MSSM, the 19-dimensional parameter space of the CP-conserving MSSM with Minimal Flavor Violation. We determined whether each of these points satisfied existing experimental and theoretical constraints. This analysis provides insight into general features of the MSSM without reference to a particular SUSY breaking scenario or any other assumptions at the GUT scale. This study opens up new possibilities for SUSY phenomenology both in colliders and in astrophysical experiments. Here we shall discuss the implications of this analysis relevant to the study of dark matter.Comment: 27 pages, 19 figs; Journal version in NJP issue "Focus on Dark Matter and Particle Physics". Previous version had 26 pages, 19 figures. Text and some figures have been update

Results from a Low-Energy Analysis of the CDMS II Germanium Data

We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs) with masses below ~10 GeV/c^2. This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c^2 and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.Comment: 9 pages, 8 figures. Supplemental material included as ancillary files. v3) Added appendix with additional details regarding energy scale and background

WIMP dark matter, Higgs exchange and DAMA

In the WIMP scenario, there is a one-to-one relation between the dark matter (DM) relic density and spin independent direct detection rate if both the annihilation of DM and its elastic scattering on nuclei go dominantly through Higgs exchange. In particular, for DM masses much smaller than the Higgs boson mass, the ratio of the relevant cross sections depends only on the DM mass. Assuming DM mass and direct detection rate within the ranges allowed by the recent DAMA collaboration results -taking account of the channelling effect on energy threshold and the null results of the other direct detection experiments- gives a definite range for the relic density. For scalar DM models, like the Higgs portal models or the inert doublet model, the relic density range turns out to be in agreement with WMAP. This scenario implies that the Higgs boson has a large branching ratio to pairs of DM particles, a prediction which might challenge its search at the LHC.Comment: 5 pages, 5 figures. Matches the published version. One figure modified. Conclusions unchange