A Dark Matter Candidate from an Extra (Non-Universal) Dimension

We show that a recently constructed five-dimensional (5D) model with gauge-Higgs unification and explicit Lorentz symmetry breaking in the bulk, provides a natural dark matter candidate. This is the lightest Kaluza-Klein particle odd under a certain discrete Z_2 symmetry, which has been introduced to improve the naturalness of the model, and resembles KK-parity but is less constraining. The dark matter candidate is the first KK mode of a 5D gauge field and electroweak bounds force its mass above the TeV scale. Its pair annihilation rate is too small to guarantee the correct relic abundance; however coannihilations with colored particles greatly enhance the effective annihilation rate, leading to realistic relic densities.Comment: 26 pages, 10 figures; v2: fig.1 corrected, one reference and some comments added, conclusions unchanged. Version to appear in JHE

Low energy antideuterons: shedding light on dark matter

Low energy antideuterons suffer a very low secondary and tertiary astrophysical background, while they can be abundantly synthesized in dark matter pair annihilations, therefore providing a privileged indirect dark matter detection technique. The recent publication of the first upper limit on the low energy antideuteron flux by the BESS collaboration, a new evaluation of the standard astrophysical background, and remarkable progresses in the development of a dedicated experiment, GAPS, motivate a new and accurate analysis of the antideuteron flux expected in particle dark matter models. To this extent, we consider here supersymmetric, universal extra-dimensions (UED) Kaluza-Klein and warped extra-dimensional dark matter models, and assess both the prospects for antideuteron detection as well as the various related sources of uncertainties. The GAPS experiment, even in a preliminary balloon-borne setup, will explore many supersymmetric configurations, and, eventually, in its final space-borne configuration, will be sensitive to primary antideuterons over the whole cosmologically allowed UED parameter space, providing a search technique which is highly complementary with other direct and indirect dark matter detection experiments.Comment: 26 pages, 7 figures; version to appear in JCA

The Role of Antimatter Searches in the Hunt for Supersymmetric Dark Matter

We analyze the antimatter yield of supersymmetric (SUSY) models with large neutralino annihilation cross sections. We introduce three benchmark scenarios, respectively featuring bino, wino and higgsino-like lightest neutralinos, and we study in detail the resulting antimatter spectral features. We carry out a systematic and transparent comparison between current and future prospects for direct detection, neutrino telescopes and antimatter searches. We demonstrate that often, in the models we consider, antimatter searches are the only detection channel which already constrains the SUSY parameter space. Particularly large antiprotons fluxes are expected for wino-like lightest neutralinos, while significant antideuteron fluxes result from resonantly annihilating binos. We introduce a simple and general recipe which allows to assess the visibility of a given SUSY model at future antimatter search facilities. We provide evidence that upcoming space-based experiments, like PAMELA or AMS, are going to be, in many cases, the unique open road towards dark matter discovery.Comment: 34 pages, 18 figures; V2: misprints in the labels of fig. 2,3 and 5 correcte

Experimental identification of non-pointlike dark-matter candidates

We show that direct dark matter detection experiments can distinguish between pointlike and non-pointlike dark-matter candidates. The shape of the nuclear recoil energy spectrum from pointlike dark-matter particles, e.g., neutralinos, is determined by the velocity distribution of dark matter in the galactic halo and by nuclear form factors. In contrast, typical cross sections of non-pointlike dark matter, for example, Q-balls, have a new form factor, which decreases rapidly with the recoil energy. Therefore, a signal from non-pointlike dark matter is expected to peak near the experimental threshold and to fall off rapidly at higher energies. Although the width of the signal is practically independent of the dark matter velocity dispersion, its height is expected to exhibit an annual modulation due to the changes in the dark matter flux.Comment: 4 pages; minor changes, references adde

Model Independent Approach to Focus Point Supersymmetry: from Dark Matter to Collider Searches

The focus point region of supersymmetric models is compelling in that it simultaneously features low fine-tuning, provides a decoupling solution to the SUSY flavor and CP problems, suppresses proton decay rates and can accommodate the WMAP measured cold dark matter (DM) relic density through a mixed bino-higgsino dark matter particle. We present the focus point region in terms of a weak scale parameterization, which allows for a relatively model independent compilation of phenomenological constraints and prospects. We present direct and indirect neutralino dark matter detection rates for two different halo density profiles, and show that prospects for direct DM detection and indirect detection via neutrino telescopes such as IceCube and anti-deuteron searches by GAPS are especially promising. We also present LHC reach prospects via gluino and squark cascade decay searches, and also via clean trilepton signatures arising from chargino-neutralino production. Both methods provide a reach out to m_{\tg}\sim 1.7 TeV. At a TeV-scale linear e^+e^- collider (LC), the maximal reach is attained in the \tz_1\tz_2 or \tz_1\tz_3 channels. In the DM allowed region of parameter space, a \sqrt{s}=0.5 TeV LC has a reach which is comparable to that of the LHC. However, the reach of a 1 TeV LC extends out to m_{\tg}\sim 3.5 TeV.Comment: 34 pages plus 36 eps figure

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

The Abundance of New Kind of Dark Matter Structures

A new kind of dark matter structures, ultracompact minihalos (UCMHs) was proposed recently. They would be formed during the radiation dominated epoch if the large density perturbations are existent. Moreover, if the dark matter is made up of weakly interacting massive particles, the UCMHs can have effect on cosmological evolution because of the high density and dark matter annihilation within them. In this paper, one new parameter is introduced to consider the contributions of UCMHs due to the dark matter annihilation to the evolution of cosmology, and we use the current and future CMB observations to obtain the constraint on the new parameter and then the abundance of UCMHs. The final results are applicable for a wider range of dark matter parametersComment: 4 pages, 1 tabl

Generalized Analysis of Weakly-Interacting Massive Particle Searches

We perform a generalized analysis of data from WIMP search experiments for point-like WIMPs of arbitrary spin and general Lorenz-invariant WIMP-nucleus interaction. We show that in the non-relativistic limit only spin-independent (SI) and spin-dependent (SD) WIMP-nucleon interactions survive, which can be parameterized by only five independent parameters. We explore this five-dimensional parameter space to determine whether the annual modulation observed in the DAMA experiment can be consistent with all other experiments. The pure SI interaction is ruled out except for very small region of parameter space with the WIMP mass close to 50 GeV and the ratio of the WIMP-neutron to WIMP-proton SI couplings $-0.77\le f_n/f_p\le -0.75$. For the predominantly SD interaction, we find an upper limit to the WIMP mass of about 18 GeV, which can only be weakened if the constraint stemming from null searches for energetic neutrinos from WIMP annihilation the Sun is evaded. None of the regions of the parameter space that can reconcile all WIMP search results can be easily accommodated in the minimal supersymmetric extension of the standard model.Comment: 27 pages, 3 figure

Direct versus indirect detection in mSUGRA with self-consistent halo models

We perform a detailed analysis of the detection prospects of neutralino dark matter in the mSUGRA framework. We focus on models with a thermal relic density, estimated with high accuracy using the DarkSUSY package, in the range favored by current precision cosmological measurements. Direct and indirect detection rates are computed implementing two models for the dark matter halo, tracing opposite regimes for the phase of baryon infall, with fully consistent density profiles and velocity distribution functions. This has allowed, for the first time, a fully consistent comparison between direct and indirect detection prospects. We discuss all relevant regimes in the mSUGRA parameter space, underlining relevant effects, and providing the basis for extending the discussion to alternative frameworks. In general, we find that direct detection and searches for antideuterons in the cosmic rays seems to be the most promising ways to search for neutralinos in these scenarios.Comment: 26 pages, 9 figure