Strong Interactive Massive Particles from a Strong Coupled Theory

Minimal walking technicolor models can provide a nontrivial solution for cosmological dark matter, if the lightest technibaryon is doubly charged. Technibaryon asymmetry generated in the early Universe is related to baryon asymmetry and it is possible to create excess of techniparticles with charge (-2). These excessive techniparticles are all captured by $^4He$, creating \emph{techni-O-helium} $tOHe$ ``atoms'', as soon as $^4He$ is formed in Big Bang Nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in Big Bang Nucleosynthesis. Due to the large mass of technibaryons, the $tOHe$ ``atomic'' gas decouples from the baryonic matter and plays the role of dark matter in large scale structure formation, while structures in small scales are suppressed. Nuclear interactions with matter slow down cosmic techni-O-helium in Earth below the threshold of underground dark matter detectors, thus escaping severe CDMS constraints. On the other hand, these nuclear interactions are not sufficiently strong to exclude this form of Strongly Interactive Massive Particles by constraints from the XQC experiment. Experimental tests of this hypothesis are possible in search for $tOHe$ in balloon-borne experiments (or on the ground) and for its charged techniparticle constituents in cosmic rays and accelerators. The $tOHe$ ``atoms'' can cause cold nuclear transformations in matter and might form anomalous isotopes, offering possible ways to exclude (or prove?) their existence.Comment: 41 pages, 4 figure

Gamma-ray effects of dark forces in dark matter clumps

Existence of new gauge U(1) symmetry possessed by dark matter (DM) particles implies the existence of a new Coulomb-like interaction, which leads to Sommerfeld-Gamow-Sakharov enhancement of dark matter annihilation at low relative velocities. We discuss a possibility to put constraints on the such dark forces of dark matter from the observational data on the gamma radiation in our Galaxy. Gamma-rays are supposed to originate from annihilation of DM particles in the small scale clumps, in which annihilation rate is supposed to be enhanced, besides higher density, due to smaller relative velocities $v$ of DM particles. For possible cross sections, mass of annihilating particles, masses of clumps and the contribution of annihilating particles in the total DM density we constrain the strength of new dark long range forces from comparison of predicted gamma ray signal with Fermi/LAT data on unidentified point-like gamma-ray sources (PGS) as well as on diffuse $\gamma$-radiation.Comment: Accepted to Advances in High Energy Physics. arXiv admin note: text overlap with arXiv:1212.608

Ultra cold neutron trap as a tool to search for dark matter with long-range radius of forces

The problem of possible application of an ultracold neutron (UCN) trap as a detector of dark matter particles with long-range radius of forces has been considered. Transmission of small recoil energy in scattering is a characteristic of long-range forces. The main advantage of the ultracold neutron technique lies in possibility of detecting recoil energy as small as $10^{-7}$ eV. Here are presented constraints on the interaction potential parameters: $U(r)=a r^{-1} e^{-r/\lambda}$ for dark matter particles and neutrons, as well as on the density value of long-range dark matter on the Earth. The possible mechanism of accumulation of long-range dark matter on the Earth surface is considered and the factor of density increase on the Earth surface is evaluated. The results of the first experiment on search of astronomical day variation of ultracold neutron storage time are under discussion.Comment: 17 pages, 19 figures. arXiv admin note: substantial text overlap with arXiv:1109.339

High Energy Positrons and Gamma Radiation from Decaying Constituents of a two-component Dark Atom Model

We study a two component dark matter candidate inspired by the Minimal Walking Technicolor model. Dark matter consists of a dominant SIMP-like dark atom component made of bound states between primordial helium nuclei and a doubly charged technilepton, and a small WIMP-like component made of another dark atom bound state between a doubly charged technibaryon and a technilepton. This scenario is consistent with direct search experimental findings because the dominant SIMP component interacts too strongly to reach the depths of current detectors with sufficient energy to recoil and the WIMP-like component is too small to cause significant amount of events. In this context a metastable technibaryon that decays to $e^+e^+$, $\mu^+ \mu^+$ and $\tau^+ \tau^+$ can in principle explain the observed positron excess by AMS-02 and PAMELA, while being consistent with the photon flux observed by FERMI/LAT. We scan the parameters of the model and we find the best possible fit to the latest experimental data. We find that there is a small range of parameter space that this scenario can be realised under certain conditions regarding the cosmic ray propagation and the final state radiation. This range of parameters fall inside the region where the current run of LHC can probe, and therefore it will soon be possible to either verify or exclude conclusively this model of dark matter.Comment: 11 pages, 4 figures, invited contribution to the special issue "Composite dark matter" of International Journal of Modern Physics D. arXiv admin note: text overlap with arXiv:1411.365

On the classical description of the recombination of dark matter particles with a Coulomb-like interaction

Cold dark matter (DM) scenario may be cured of several problems by involving self-interaction of dark matter. Viability of the models of long-range interacting DM crucially depends on the effectiveness of recombination of the DM particles, making thereby their interaction short-range. Usually in numeric calculations, recombination is described by cross section obtained on a feasible quantum level. However in a wide range of parameter values, a classical treatment, where the particles are bound due to dipole radiation, is applicable. The cross sections, obtained in both approaches, are very different and lead to diverse consequences. Classical cross section has a steeper dependence on relative velocity, what leads to the fact that, after decoupling of DM particles from thermal background of "dark photons" (carriers of DM long-range interaction), recombination process does not "freeze out", diminishing gradually density of unbound DM particles. Our simplified estimates show, that at the taken parameter values (the mass of DM particle is $100$ GeV, interaction constant is $100^{-1}$, and quite natural assumptions on initial conditions, from which the result is very weakly dependent) the difference in residual density reaches about $5$ orders of magnitude on pre-galactic stage. This estimate takes into account thermal effects induced by dipole radiation and recombination, which resulted in the increase of both temperature and density of DM particles by a half order of magnitude.Comment: 11 pages, 4 figures. V3 has tiny corrections, matches published versio

Constraints on the Dark Matter Particle Mass from the Number of Milky Way Satellites

We have conducted N-body simulations of the growth of Milky Way-sized halos in cold and warm dark matter cosmologies. The number of dark matter satellites in our simulated Milky Ways decreases with decreasing mass of the dark matter particle. Assuming that the number of dark matter satellites exceeds or equals the number of observed satellites of the Milky Way we derive lower limits on the dark matter particle mass. We find with 95% confidence m_s > 13.3 keV for a sterile neutrino produced by the Dodelson and Widrow mechanism, m_s > 8.9 keV for the Shi and Fuller mechanism, m_s > 3.0 keV for the Higgs decay mechanism, and m_{WDM} > 2.3 keV for a thermal dark matter particle. The recent discovery of many new dark matter dominated satellites of the Milky Way in the Sloan Digital Sky Survey allows us to set lower limits comparable to constraints from the complementary methods of Lyman-alpha forest modeling and X-ray observations of the unresolved cosmic X-ray background and of dark matter halos from dwarf galaxy to cluster scales. Future surveys like LSST, DES, PanSTARRS, and SkyMapper have the potential to discover many more satellites and further improve constraints on the dark matter particle mass.Comment: 17 pages, 13 figures, replaced with final version published in Physical Review