Effects of Squark Processes on the Axino CDM Abundance

We investigate the role of an effective dimension-4 axino-quark-squark coupling in the thermal processes producing stable cold axino relics in the early Universe. We find that, while the induced squark and quark scattering processes are always negligible, squark decays become important in the case of low reheat temperature and large gluino mass. The effect can tighten the bounds on the scenario from the requirement that cold dark matter axinos do not overclose the Universe.Comment: 20 pages, 9 figures, uses JHEP3.cl

On prospects for dark matter indirect detection in the Constrained MSSM

In the framework of the Constrained MSSM we derive the most probable ranges of the diffuse gamma radiation flux from the direction of the Galactic center and of the positron flux from the Galactic halo due to neutralino dark matter annihilation. We find that, for a given halo model, and assuming flat priors, the 68% probability range of the integrated gamma-ray flux spans about one order of magnitude, while the 95% probability range can be much larger and extend over four orders of magnitude (even exceeding five for a tiny region at small neutralino mass). The detectability of the signal by GLAST depending primarily on the cuspiness of the halo profile. The positron flux, on the other hand, appears to be too small to be detectable by PAMELA, unless the boost factor is at least of order ten and/or the halo profile is extremely cuspy. We also briefly discuss the sensitivity of our results to the choice of priors

Efficient reconstruction of CMSSM parameters from LHC data - A case study

We present an efficient method of reconstructing the parameters of the Constrained MSSM from assumed future LHC data, applied both on their own right and in combination with the cosmological determination of the relic dark matter abundance. Focusing on the ATLAS SU3 benchmark point, we demonstrate that our simple Gaussian approximation can recover the values of its parameters remarkably well. We examine two popular non-informative priors and obtain very similar results, although when we use an informative, naturalness-motivated prior, we find some sizeable differences. We show that a further strong improvement in reconstructing the SU3 parameters can by achieved by applying additional information about the relic abundance at the level of WMAP accuracy, although the expected data from Planck will have only a very limited additional impact. Further external data may be required to break some remaining degeneracies. We argue that the method presented here is applicable to a wide class of low-energy effective supersymmetric models, as it does not require to deal with purely experimental issues, eg, detector performance, and has the additional advantages of computational efficiency. Furthermore, our approach allows one to distinguish the effect of the model's internal structure and of the external data on the final parameters constraints.Comment: 23 pages, 10 figures - moderate revision: includes naturalness prior. Matches published versio

Directional detection of Dark Matter

Among the many experimental techniques available, those providing directional information have the potential of yielding an unambiguous observation of WIMPs even in the presence of insidious backgrounds. A measurement of the distribution of arrival direction of WIMPs can also discriminate between Galactic Dark Matter halo models. In this article, I will discuss the motivation for directional detectors and review the experimental techniques used by the various experiments. I will then describe one of them, the DMTPC detector, in more detail.Comment: 17 pages, 11 postscript figures, mini-review submitted to Modern Physics Letters A (MPLA). Submitted to Modern Physics Letters A (MPLA

Exact Cross Sections for the Neutralino-Slepton Coannihilation

Coannihilation processes provide an important additional mechanism for reducing the density of stable relics in the Universe. In the case of the stable lightest neutralino of the MSSM, and in particular the Constrained MSSM (CMSSM), the coannihilation with sleptons plays a major role in opening up otherwise cosmologically excluded ranges of supersymmetric parameters. In this paper, we derive a full set of exact, analytic expressions for the coannihilation of the lightest neutralino with the sleptons into all two--body tree--level final states in the framework of minimal supersymmetry. We make no simplifying assumptions about the neutralino nor about sfermion masses and mixings other than the absence of explicit CP--violating terms and inter--family mixings. The expressions should be particularly useful in computing the neutralino WIMP relic abundance without the approximation of partial wave expansion. We illustrate the effect of our analytic results with numerical examples and demonstrate a sizeable difference with approximate expressions available in the literature.Comment: LaTeX, 46 pages, 8 eps figure

A New Model-Independent Method for Extracting Spin-Dependent Cross Section Limits from Dark Matter Searches

A new method is proposed for extracting limits on spin-dependent WIMP-nucleon interaction cross sections from direct detection dark matter experiments. The new method has the advantage that the limits on individual WIMP-proton and WIMP-neutron cross sections for a given WIMP mass can be combined in a simple way to give a model-independent limit on the properties of WIMPs scattering from both protons and neutrons in the target nucleus. Extension of the technique to the case of a target material consisting of several different species of nuclei is discussed.Comment: 15 pages, 6 Encapsulated Postscript figure

Upper and Lower Limits on Neutralino WIMP Mass and Spin--Independent Scattering Cross Section, and Impact of New (g-2)_{mu} Measurement

We derive the allowed ranges of the spin--independent interaction cross section \sigsip for the elastic scattering of neutralinos on proton for wide ranges of parameters of the general Minimal Supersymmetric Standard Model. We investigate the effects of the lower limits on Higgs and superpartner masses from colliders, as well as the impact of constraints from \bsgamma and the new measurement of \gmtwo on the upper and lower limits on \sigsip. We further explore the impact of the neutralino relic density, including coannihilation, and of theoretical assumptions about the largest allowed values of the supersymmetric parameters. For $\mu>0$, requiring the latter to lie below 1\tev leads to \sigsip\gsim 10^{-11}\pb at \mchi\sim100\gev and \sigsip\gsim 10^{-8}\pb at \mchi\sim1\tev. When the supersymmetric parameters are allowed above 1\tev, for 440\gev \lsim \mchi\lsim 1020 \gev we derive a {\em parameter--independent lower limit} of \sigsip \gsim 2\times 10^{-12}\pb. (No similar lower limits can be set for $\mu<0$ nor for 1020\gev\lsim\mchi\lsim2.6\tev.) Requiring \abundchi<0.3 implies a {\em parameter--independent upper limit} \mchi\lsim2.6\tev. The new \epem--based measurement of $(g-2)_{\mu}$ restricts \mchi\lsim 350\gev at $1 \sigma$ CL and \mchi\lsim515\gev at $2 \sigma$ CL, and implies $\mu>0$. The largest allowed values of \sigsip have already become accessible to recent experimental searches.Comment: LaTeX, 17 pages, 9 eps figures. Version to appear in JHE