Search For Neutralino Dark Matter Research Articles

Impact of the bounds on the direct search for neutralino dark matter on naturalness

In the Minimal Supersymmetric Extension of the Standard Model (MSSM) the higgsino mass parameter $\mu$ appears both in the masses of the Higgs bosons and in the neutralino mass matrix. Electroweak finetuning therefore prefers small values of $|\mu|$. On the other hand, bino--like neutralinos make a good dark matter candidate. We show that current direct search limits then impose a strong lower bound on $|\mu|$, in particular for $\mu > 0$ or if the masses of the heavy Higgs bosons of the MSSM are near their current limit from LHC searches. There is therefore some tension between finetuning and neutralino dark matter in the MSSM. We also provide simple analytical expressions which in most cases closely reproduce the numerical results.

Annihilation of NMSSM neutralinos in the Sun and neutrino telescope limits

We investigate neutralino dark matter in the framework of NMSSM performing a scan over its parameter space and calculating neutralino capture and annihilation rates in the Sun. We discuss the prospects of searches for neutralino dark matter in neutrino experiments depending on neutralino content and its main annihilation channel. We recalculate the upper limits on neutralino-proton elastic cross sections directly from neutrino telescopes upper bounds on annihilation rates in the Sun. This procedure has advantages as compared with corresponding recalcalations from the limits on muon flux, namely, it is independent on details of the experiment and the recalculation coefficients are universal for any kind of WIMP dark matter models. We derive 90% c.l. upper limits on neutralino-proton cross sections from the results of the Baksan Underground Scintillator Telescope.

Complementarity of gamma-ray and CERN LHC searches for neutralino dark matter in the focus point region

We study the complementarity between the indirect detection of dark matter with $\ensuremath{\gamma}$-rays in H.E.S.S. and the supersymmetry searches with ATLAS at the Large Hadron Collider (LHC) in the focus point region within the mSUGRA framework. The sensitivity of the central telescope of the H.E.S.S. II experiment with an energy threshold of $\ensuremath{\sim}20\text{ }\text{ }\mathrm{GeV}$ is investigated. We show that the detection of $\ensuremath{\gamma}$-ray fluxes of $\mathcal{O}({10}^{\ensuremath{-}12})\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}\text{ }{\mathrm{s}}^{\ensuremath{-}1}$ with H.E.S.S. II covers a substantial part of the focus point region which may be more difficult for LHC experiments. Despite the presence of multi-TeV scalars, we show that LHC will be sensitive to a complementary part of this region through three-body next-to-lightest supersymmetric particle leptonic decays. This interesting complementarity between H.E.S.S. II and LHC searches is further highlighted in terms of the gluino mass and the two lightest neutralino mass difference.

High energy neutrinos from neutralino annihilations in the Sun

Neutralino annihilations in the Sun to weak boson and top-quark pairs lead to high-energy neutrinos that can be detected by the IceCube and KM3 experiments in the search for neutralino dark matter. We calculate the neutrino signals from real and virtual WW, ZZ, Zh, and tt production and decays, accounting for the spin dependences of the matrix elements, which can have important influences on the neutrino energy spectra. We take into account neutrino propagation including neutrino oscillations, matter-resonance, absorption, and {nu}{sub {tau}} regeneration effects in the Sun and evaluate the neutrino flux at the Earth. We concentrate on the compelling focus point (FP) region of the supergravity model that reproduces the observed dark matter relic density. For the FP region, the lightest neutralino has a large bino-Higgsino mixture that leads to a high neutrino flux and the spin-dependent neutralino capture rate in the Sun is enhanced by 10{sup 3} over the spin-independent rate. For the standard estimate of neutralino captures, the muon signal rates in IceCube are identifiable over the atmospheric neutrino background for neutralino masses above M{sub Z} up to 400 GeV.

Indirect search for neutralino dark matter with high energy neutrinos

We investigate the prospects of indirect searches for the supersymmetric neutralino dark matter with high energy neutrinos produced from neutralino annihilations in the Sun. Muon neutrinos of this origin can be seen in large detectors like the AMANDA, the IceCube, and the ANTARES. We make realistic estimates for the indirect detection rates including effects of the muon detection threshold, quark hadronization, and solar absorption. In the minimal supersymmetric model and supergravity unified models, we find good prospects for detection of neutralinos with mass above 200 GeV.

Indirect search for neutralino dark matter with high energy neutrinos

We investigate the prospects of indirect searches for supersymmetric neutralino dark matter. Relic neutralinos gravitationally accumulate in the Sun and their annihilations produce high energy neutrinos. Muon neutrinos of this origin can be seen in large detectors like AMANDA, IceCube and ANTARES. We evaluate the relic density and the detection rate in several models---the minimal supersymmetric model, minimal supergravity, and supergravity with non-universal Higgs boson masses at the grand unification scale. We make realistic estimates for the indirect detection rates including effects of the muon detection threshold, quark hadronization, and solar absorption. We find good prospects for detection of neutralinos with mass above 200 GeV.

A new investigation on neutralino dark matter: relic density and detection rates

The main properties of the neutralino dark matter are revisited in the light of the new theoretical developments in Susy theories and of the recent constraints from accelerators and underground experiments. The neutralino relic abundance and the detection rates relevant for direct and indirect searches are evaluated in the minimal supersymmetric standard model (MSSM) with the full inclusion of the (one-loop) radiative corrections, both to the Higgs masses and to the trilinear Higgs self-coupling. The relevance of these corrections for the neutralino-neutralino annihilation cross-section, and thus for the relic density, is discussed in detail. Large regions of the parameter space are considered, including those where the neutralino only provides a fraction of the local dark matter density; in these domains the standard value for the local density is appropriately scaled down. Some general properties of the detection rates as functions of the MSSM parameters are also elucidated; in particular it is shown that in the regions of the parameter space where scaling of the local density occurs, the rates are largely independent of two of the model free parameters. The relevance of the Kamiokande upper bounds to the upgoing muon fluxes is discussed in connection with the possible neutrino outputs from the Earth and from the Sun due to neutralino accumulation and annihilation in these macroscopic bodies. Finally, the complementarity between the search for neutralino dark matter and the discovery potential of future accelerators is discussed.

Analysis of direct searches for neutralino dark matter

Analysis of direct searches for neutralino dark matter

DIRECT VERSUS INDIRECT SEARCHES FOR NEUTRALINO DARK MATTER

Direct search for neutralino dark matter is analyzed in the framework of the minimal supersymmetric extension of the standard model, using a realistic evaluation of the neutralino relic abundance which also includes radiative corrections to the Higgs masses. Relevance of the present (Ge detectors) experimental data to set constraints on the parameters of the model is discussed and expectations for future experiments which involve neutralino-nucleus coherent processes are investigated. These results are compared to those obtained in a previous paper from indirect search data. In the present analysis particular attention is paid to the theoretical uncertainties due to the different estimates of the Higgs-nucleon coupling strength.