120 research outputs found
Status of direct and indirect dark matter searches
I review the current status of dark matter searches using direct, indirect
and accelerator techniques. A detailed review of individual experiments is
beyond the scope of these proceedings. I focus instead on the challenges
(sometimes limitations) faced by each of the approaches, which is what make
them complementary, and the reason we must ensure that they are developed
concurrently.Comment: Proceedings of European Physical Society Conference on High Energy
Physics - EPS-HEP2019, 10-17 July, 2019. Submitted to Proceedings of Scienc
Closing the Window on Strongly Interacting Dark Matter with IceCube
We use the recent results on dark matter searches of the 22-string IceCube
detector to probe the remaining allowed window for strongly interacting dark
matter in the mass range 10^4<m_X<10^15 GeV. We calculate the expected signal
in the 22-string IceCube detector from the annihilation ofsuch particles
captured in the Sun and compare it to the detected background. As a result, the
remaining allowed region in the mass versus cross sectionparameter space is
ruled out. We also show the expected sensitivity of the complete IceCube
detector with 86 strings.Comment: 5 pages, 7 figures. Uppdated figures 2 and 3 (y-axis normalization
and label) . Version accepted for publication in PR
Impact of nucleon matrix element uncertainties on the interpretation of direct and indirect dark matter search results
We study in detail the impact of the current uncertainty in nucleon matrix elements on the sensitivity of direct and indirect experimental techniques for dark matter detection. We perform two scans in the framework of the cMSSM: one using recent values of the pion-sigma term obtained from Lattice QCD, and the other using values derived from experimental measurements. The two choices correspond to extreme values quoted in the literature and reflect the current tension between different ways of obtaining information about the structure of the nucleon. All other inputs in the scans, astrophysical and from particle physics, are kept unchanged. We use two experiments, XENON100 and IceCube, as benchmark cases to illustrate our case. We find that the interpretation of dark matter search results from direct detection experiments is more sensitive to the choice of the central values of the hadronic inputs than the results of indirect search experiments. The allowed regions of cMSSM parameter space after including XENON100 constrains strongly differ depending on the assumptions on the hadronic matrix elements used. On the other hand, the constraining potential of IceCube is almost independent of the choice of these values.We thank the Kavli Institute for Theoretical Physics at UCSB and organizers of the Hunting for Dark Matter programme for their hospitality during the preparation of this manuscript. This research was supported in part by the National Science Foundation under Grant No. NSF PHY11-25915. R. RdA, is supported by the Ramon y Cajal program of the Spanish MICINN and also thanks the support of the Spanish MICINN's Consolider-Ingenio 2010 Programme under the grant MULTIDARK CSD2209-00064 and the Invisibles European ITN project (FP7-PEOPLE-2011-ITN, PITN-CA-2011-289442-INVISIBLES). The use of IFT-UAM High Performance Computing Service is gratefully acknowledged.Peer reviewe
Assessing the sensitivity of PINGU to effective dark matter-nucleon interactions
We calculate the sensitivity of next generation neutrino telescopes to the 28
(isoscalar and isovector) coupling constants defining the non-relativistic
effective theory of (spin 1/2) dark matter (DM)-nucleon interactions. We take
as a benchmark detector the proposed Precision IceCube Next Generation Upgrade
(PINGU), although our results are valid for any other neutrino telescope of
similar effective volume. We express PINGU's sensitivity in terms of
sensitivity contours in the DM-mass - coupling constant plane, and compare our
sensitivity contours with the 90% C.L. exclusion limits on the same coupling
constants that we obtain from a reanalysis of the null result of current DM
searches at IceCube/DeepCore. We find that PINGU can effectively probe not only
the canonical spin-independent and spin-dependent DM-nucleon interactions, but
also velocity-dependent or momentum-dependent interactions that generate
coherently enhanced DM-nucleus scattering cross sections. We also find that
PINGU's sensitivity contours are significantly below current
IceCube/DeepCore 90% C.L. exclusion limits when is the leading DM
annihilation channel. This result shows the importance of lowering the
experimental energy threshold when probing models that generate soft neutrino
energy spectra, and holds true independently of the assumed DM-nucleon
interaction and for all DM masses tested here. When DM primarily annihilates
into , a PINGU-like detector will improve upon current
exclusion limits for DM masses below GeV, independently of the assumed
DM-nucleon interaction.Comment: 20 pages, 6 figures and 1 tabl
Constraints on Enhanced Dark Matter Annihilation from IceCube Results
Excesses on positron and electron fluxes measured by ATIC, and the PAMELA and
Fermi--LAT telescopes can be explained by dark matter annihilation in our
Galaxy. However, this requires large boosts on the dark matter annihilation
rate. There are many possible enhancement mechanisms, such as the Sommerfeld
effect or the existence of dark matter clumps in our halo. If enhancements on
the dark matter annihilation cross section are taking place, the dark matter
annihilation in the core of the Earth should also be enhanced. Here we use
recent results from the IceCube 40-string configuration to probe generic
enhancement scenarios. We present results as a function of the dark
matter-proton interaction cross section, weighted by the
branching fraction into neutrinos, , as a function of a
generic boost factor, , which parametrizes the expected enhancement of the
annihilation rate. We find that dark matter models which require annihilation
enhancements of or more and that annihilate significantly
into neutrinos are excluded as the explanation for these excesses. We also
determine the boost range that can be probed by the full IceCube telescope.Comment: 6 pages, 3 figures; version accepted for publicatio
Prospects for dark matter detection with IceCube in the context of the CMSSM
We study in detail the ability of the nominal configuration of the IceCube
neutrino telescope (with 80 strings) to probe the parameter space of the
Constrained MSSM (CMSSM) favoured by current collider and cosmological data.
Adopting conservative assumptions about the galactic halo model and the
expected experiment performance, we find that IceCube has a probability between
2% and 12% of achieving a 5sigma detection of dark matter annihilation in the
Sun, depending on the choice of priors for the scalar and gaugino masses and on
the astrophysical assumptions. We identify the most important annihilation
channels in the CMSSM parameter space favoured by current constraints, and we
demonstrate that assuming that the signal is dominated by a single annihilation
channel canlead to large systematic errors in the inferred WIMP annihilation
cross section. We demonstrate that ~ 66% of the CMSSM parameter space violates
the equilibrium condition between capture and annihilation in the center of the
Sun. By cross-correlating our predictions with direct detection methods, we
conclude that if IceCube does detect a neutrino flux from the Sun at high
significance while direct detection experiments do not find a signal above a
spin-independent cross section sigma_SI^p larger than 5x10^{-9} pb, the CMSSM
will be strongly disfavoured, given standard astrophysical assumptions for the
WIMP distribution. This result is robust with respect to a change of priors. We
argue that the proposed low-energy DeepCore extension of IceCube will be an
ideal instrument to focus on relevant CMSSM areas of parameter space.Comment: 32 pages, 12 figures. Updated discussion of comparison with direct
detection. References added. Main results unchanged. Matches version accepted
by JCA
In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory
The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p
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