Implications of collider experiments for detecting cold dark matter

By investigating the space of parameters of the minimal supersymmetric extension of the Standard Model, it is shown that an observation of at least one supersymmetric particle in high-energy experiments would increase considerably the importance of highly sensitive low-energy experiments aimed at detecting cold-dark-matter particles assumed to be neutralinos, the lightest supersymmetric particles, which are stable. On the other hand, nonobservation of direct signals from dark matter in such experiments can have a pronounced effect on the strategy of high-energy searches for the light charged Higgs boson.     

Prospects for detecting supersymmetric dark matter at Post-LEP benchmark points

A new set of supersymmetric benchmark scenarios has recently been proposed in the context of the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking masses, taking into account the constraints from LEP, and . These points have previously been used to discuss the physics reaches of different accelerators. In this paper, we discuss the prospects for discovering supersymmetric dark matter in these scenarios. We consider direct detection through spin-independent and spin-dependent nuclear scattering, as well as indirect detection through relic annihilations to neutrinos, photons, and positrons. We find that several of the benchmark scenarios offer good prospects for direct detection via spin-independent nuclear scattering and indirect detection via muons produced by neutrinos from relic annihilations inside the Sun, and some models offer good prospects for detecting photons from relic annihilations in the galactic centre. Received: 17 October 2001 / Revised version: 14 January 2002 / Published online: 12 April 2002     

Collider search of light dark matter model with dark sector decay

We explore the possibility that the dark matter relic density is not produced by a thermal mechanism directly, but by the decay of other heavier dark-sector particles which themselves can be produced by the thermal freeze-out mechanism. Using a concrete model with light dark matter from dark sector decay, we study the collider signature of the dark sector particles associated with Higgs production processes. We find that future lepton colliders could be a better place to probe the signature of this kind of light dark matter model than hadron colliders such as LHC. Also, we find that a Higgs factory with center-of-mass energy 250 GeV has a better potential to resolve the signature of this kind of light dark matter model than a Higgs factory with center-of-mass energy 350 GeV.     

Holographic technicolor model and dark matter

We investigate the strongly coupled minimal walking technicolor model (MWT) in the framework of a bottom-up holographic model, where the global \begin{document}$ SU(4)$\end{document} symmetry breaks into \begin{document}$ SO(4)$\end{document} subgroups. In the holographic model, we found that 125 GeV composite Higgs particles and small Peskin–Takeuchi S parameter can be achieved simultaneously. In addition, the model predicts a large number of particles at the TeV scale, including dark matter candidates Technicolor Interacting Massive Particles (TIMPs). If we consider the dark matter nuclear spin-independent cross-section in the range of \begin{document}$ 10^{-45}\sim 10 ^ {-48} \;{\rm{cm}}^2$\end{document}, which can be detected by future experiments, the mass range of TIMPs predicted by the holographic technicolor model is \begin{document}$ 2 \sim 4$\end{document} TeV.     

Axion condensate as a model for dark matter halos

Localized solutions of an axion-like scalar model with a periodic self-interaction are analyzed as a model of dark matter halos. It is shown that such a cold Bose–Einstein type condensate can provide a substantial contribution to the observed rotations curves of galaxies, as well provide a soliton type interpretation of the dark matter ‘bullets’ observed via gravitational lensing in merging clusters.     

Cold dark matter in the doublet-triplet model

We analyze in detail a particle physics model which gives rise to light neutrinos as the cold dark matter of the universe. Contrary to the Gelmini-Roncadelli model, our model requires an explicit breaking of the B−L quantum number in the lagrangian.     

Difficulty of detecting minihalos via gamma rays from dark matter annihilation

Analytical calculations and recent numerical experiments have shown that a sizable amount of the mass of our Galaxy is in a form of clumpy, virialized substructures that, according to Diemand et al., can be as light as 10(-6)M(.). In this work we estimate the gamma-ray flux expected from dark matter annihilation occurring within these minihalos, under the hypothesis that the bulk of dark matter is composed by neutralinos. We generate mock sky maps showing the angular distribution of the expected gamma-ray signal. We compare them with the sensitivities of satellite-borne experiments such as GLAST and find that a possible detection of minihalos is indeed very challenging.     

Constraints on the unified model of dark matter and dark energy

Using recently observed data:the Constitution dataset of type supernovae Ia (SNIa),the observational Hubble data (OHD),the measurement results of baryon acoustic oscillation (BAO) from the Sloan Digital Sky Survey (SDSS) and the Two Degree Field Galaxy Redshift Survey (2dFGRS),and the current cosmic microwave background (CMB) data from the five-year Wilkinson Microwave Anisotropy Probe (WMAP),we apply the Markov Chain Monte Carlo method to investigate the observational constraints on the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy.For this unified model,the constraints on GCG mixture are discussed by considering the different expressions of current matter density or considering constraints as being independent of the matter quantity Ωm.     

Braneworld model of dark matter: structure formation

Following a previous work (García-Aspeitia in Gen Rel Grav 43:315–329, 2011), we further study the behavior of a real scalar field in a hidden brane in a configuration of two branes embedded in a five dimensional bulk. We find an expression for the equation of state for this scalar field in the visible brane in terms of the fields of the hidden one. Additionally, we investigated the perturbations produced by this scalar field in the visible brane with the aim to study their dynamical properties. Our results show that if the kinetic energy of the scalar field dominates during the early universe the perturbed scalar field could mimic the observed dynamics for the dark matter in the standard paradigm. Thus, the scalar field dark matter hypothesis in the context of braneworld theory could be an interesting alternative to the nature of dark matter in the Universe.     

Unified model of baryonic matter and dark components

We investigate an interacting two-fluid cosmological model and introduce a scalar field representation by means of a linear combination of the individual energy densities. Applying the integrability condition to the scalar field equation we show that this “exotic quintessence” is driven by an exponential potential and the two-fluid mixture can be considered as a model of three components. These components are associated with baryonic matter, dark matter and dark energy respectively. We use the Simon, Verde and Jimenez [J. Simon, L. Verde, R. Jimenez, Phys. Rev. D 71 (2005) 123001] determination of the redshift dependence of the Hubble parameter to constrain the current density parameters of this model. With the best fit density parameters we obtain the transition redshift between non-accelerated and accelerated regimes zacc=0.66$z_{\mathrm{acc}}=0.66$ and the time elapsed since the initial singularity t₀=19.8 Gyr$t_0=19.8\text{Gyr}$. We study the perturbation evolution of this model and find that the energy density perturbation decreases with the cosmological time.     

Quark mixing in the discrete dark matter model

We consider a model in which dark matter is stable as it is charged under a Z₂ symmetry that is residual after an A₄ flavour symmetry is broken. We consider the possibility to generate the quark masses by charging the quarks appropriately under A₄. We find that it is possible to generate the CKM mixing matrix by an interplay of renormalisable and dimension-six operators. In this set-up, we predict the third neutrino mixing angle to be large and the dark matter relic density to be in the correct range. Low energy observables - in particular meson-antimeson oscillations - are hard to facilitate. We find that only in a situation where there is a strong cancellation between the Standard Model contribution and the contribution of the new Higgs fields, B meson oscillations are under control.     

Supersymmetric extension of the minimal dark matter model

The minimal dark matter model is given a supersymmetric extension. A super SU(2)_L quintuplet is introduced with its fermionic neutral component still being the dark matter, and the dark matter mass is about 19.7 TeV. Mass splitting among the quintplet due to supersymmetry particles is found to be negligibly small compared to the electroweak corrections. Other properties of this supersymmetry model are studied, it has the solutions to the PAMELA and Fermi-LAT anomaly, and the predictions in higher energies need further experimental data to verify them.     

Status of the scalar singlet dark matter model

One of the simplest viable models for dark matter is an additional neutral scalar, stabilised by a \(\mathbb {Z}_2\) symmetry. Using the GAMBIT package and combining results from four independent samplers, we present Bayesian and frequentist global fits of this model. We vary the singlet mass and coupling along with 13 nuisance parameters, including nuclear uncertainties relevant for direct detection, the local dark matter density, and selected quark masses and couplings. We include the dark matter relic density measured by Planck, direct searches with LUX, PandaX, SuperCDMS and XENON100, limits on invisible Higgs decays from the Large Hadron Collider, searches for high-energy neutrinos from dark matter annihilation in the Sun with IceCube, and searches for gamma rays from annihilation in dwarf galaxies with the Fermi-LAT. Viable solutions remain at couplings of order unity, for singlet masses between the Higgs mass and about 300 GeV, and at masses above \(\sim \)1 TeV. Only in the latter case can the scalar singlet constitute all of dark matter. Frequentist analysis shows that the low-mass resonance region, where the singlet is about half the mass of the Higgs, can also account for all of dark matter, and remains viable. However, Bayesian considerations show this region to be rather fine-tuned.     

Model for cold dark matter

We present a model for cold dark matter based upon continuum bound states of thee ⁺ e ^– system. These continuum bound states, referred to as photonium states to distinguish them from the well-known bound states of positronium, are shown to have cross sections and lifetime properties consistent with abundant production in the early universe and survival to the present time. Thus photonium can easily account for more than 90% of the total mass of the universe.The authors have benefitted from discussions with Charles J. Benesh. This work was supported in part by the US DOE grant no. DE-FG02-87ER40371, Division of High Energy and Nuclear Physics and by contract no. W-7405-ENG-82.     

Indirect searches for dark matter with AMS-02

AMS-02 is a multi-purpose spectrometer with superconducting magnet, and is designed for 3 years of data taking aboard the International Space Station. Its high performance regarding particle identification and energy measurement will allow performing indirect searches for dark matter (DM) in different channels simultaneously: gamma rays, positrons and antiprotons. AMS-02 sensitivity to those signals are presented and – provided the positron excess is due to DM signal – it is shown that it allows to probe new physics models in detail. Its high sensitivity could even be a unique opportunity to reach the Majorana nature of the DM particle through final state polarization effects. PACS  95.35.+d; 95.55.Vj     

Galactic searches for dark matter

For nearly a century, more mass has been measured in galaxies than is contained in the luminous stars and gas. Through continual advances in observations and theory, it has become clear that the dark matter in galaxies is not comprised of known astronomical objects or baryonic matter, and that identification of it is certain to reveal a profound connection between astrophysics, cosmology, and fundamental physics. The best explanation for dark matter is that it is in the form of a yet undiscovered particle of nature, with experiments now gaining sensitivity to the most well-motivated particle dark matter candidates. In this article, I review measurements of dark matter in the Milky Way and its satellite galaxies and the status of Galactic searches for particle dark matter using a combination of terrestrial and space-based astroparticle detectors, and large scale astronomical surveys. I review the limits on the dark matter annihilation and scattering cross sections that can be extracted from both astroparticle experiments and astronomical observations, and explore the theoretical implications of these limits. I discuss methods to measure the properties of particle dark matter using future experiments, and conclude by highlighting the exciting potential for dark matter searches during the next decade, and beyond.     

Indirect searches for dark matter

The current status of indirect searches for dark matter has been reviewed in a schematic way here. The main relevant experimental results of the recent years have been listed and the excitements and disappointments that their phenomenological interpretations in terms of almost-standard annihilating dark matter have brought along have been discussed. The main sources of uncertainties that affect this kind of searches are also listed. [Report number: Saclay T11/206, CERN-PH-TH/2011-257, extended version in arXiv:1202.1454], [Prepared for the Proceedings of Lepton?CPhoton 2011, Mumbai, India, 22?C27 Aug. 2011].