WorldWideScience

Sample records for baryonic dark matter

  1. Baryonic Dark Matter

    OpenAIRE

    Paolis, F.; Ingrosso, G.; Jetzer, Ph.; Roncadelli, M.

    1997-01-01

    Reasons supporting the idea that most of the dark matter in galaxies and clusters of galaxies is baryonic are discussed. Moreover, it is argued that most of the dark matter in galactic halos should be in the form of MACHOs and cold molecular clouds.

  2. Baryonic dark matter

    International Nuclear Information System (INIS)

    Dark matter, first definitely found in the large clusters of galaxies, is now known to be dominant mass in the outer parts of galaxies. All the mass definitely deduced could be made up of baryons, and this would fit well with the requirements of nucleosynthesis in a big bang of small ΩB. However, if inflation is the explanation of the expansion and large scale homogeneity of the universe and of baryon synthesis, and if the universe did not have an infinite extent at the big bang, then Ω should be minutely greater than unity. It is commonly hypothesized that most mass is composed of some unknown, non-baryonic form. This book first discusses the known forms, comets, planets, brown dwarfs, stars, gas, galaxies and Lyman α clouds in which baryons are known to exist. Limits on the amount of dark matter in baryonic form are discussed in the context of the big bang. Inhomogeneities of the right type alleviate the difficulties associated with ΩB = 1 cosmological nucleosynthesis

  3. Baryonic and Non-Baryonic Dark Matter

    OpenAIRE

    Carr, Bernard

    2000-01-01

    Cosmological nucleosynthesis calculations imply that there should be both non-baryonic and baryonic dark matter. Recent data suggest that some of the non-baryonic dark matter must be "hot" (i.e. massive neutrinos) and there may also be evidence for "cold" dark matter (i.e. WIMPs). If the baryonic dark matter resides in galactic halos, it is likely to be in the form of compact objects (i.e. MACHOs) and these would probably be the remnants of a first generation of pregalactic or protogalactic P...

  4. Non-Baryonic Dark Matter

    OpenAIRE

    Bergstrom, L.

    2001-01-01

    The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and to some extent massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Present experiments are just reaching the required sensitivity...

  5. Crypto-baryonic Dark Matter

    CERN Document Server

    Froggatt, C D

    2005-01-01

    It is proposed that dark matter could consist of compressed collections of atoms (or metallic matter) encapsulated into, for example, 20 cm big pieces of a different phase. The idea is based on the assumption that there exists at least one other phase of the vacuum degenerate with the usual one. Apart from the degeneracy of the phases we only assume Standard Model physics. The other phase has a Higgs VEV appreciably smaller than in the usual electroweak vacuum. The balls making up the dark matter are very difficult to observe directly, but inside dense stars may expand eating up the star and cause huge explosions (gamma ray bursts). The ratio of dark matter to ordinary baryonic matter is estimated to be of the order of the ratio of the binding energy per nucleon in helium to the difference between the binding energies per nucleon in heavy nuclei and in helium. Thus we predict approximately five times as much dark matter as ordinary baryonic matter!

  6. Non-Baryonic Dark Matter

    CERN Document Server

    Bergström, L

    1999-01-01

    The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and to some extent massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the next few years.

  7. Non-baryonic dark matter

    International Nuclear Information System (INIS)

    The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and to some extent massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the next few years

  8. Dark Matter Assimilation into the Baryon Asymmetry

    CERN Document Server

    D'Eramo, Francesco; Thaler, Jesse

    2011-01-01

    Pure singlets are typically disfavored as dark matter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new dark matter mechanism called "assimilation", which takes advantage of the baryon asymmetry of the universe to generate the correct relic abundance of singlet dark matter. Through assimilation, dark matter itself is efficiently destroyed, but dark matter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) dark matter as well as (asymmetric) standard model baryons. We study in detail the case of pure bino dark matter by augmenting the minimal supersymmetric standard model with vector-like chiral multiplets. In the parameter range where this mechanism is effective, the LHC can discover long-lived charged particles which were responsible for assimilating dark matter.

  9. Non-Baryonic Dark Matter in Cosmology

    CERN Document Server

    Del Popolo, A

    2014-01-01

    This paper is a broad-band review of the current status of non-baryonic dark matter research. I start with a historical overview of the evidences of dark matter existence, then I discuss how dark matter is distributed from small scale to large scale, and I then verge the attention to dark matter nature: dark matter candidates and their detection. I finally discuss some of the limits of the $\\Lambda$CDM model, with particular emphasis on the small scale problems of the paradigm.

  10. Non-Baryonic Dark Matter in Cosmology

    OpenAIRE

    Del Popolo, A.

    2013-01-01

    This paper is a broad-band review of the current status of non-baryonic dark matter research. I start with a historical overview of the evidences of dark matter existence, then I discuss how dark matter is distributed from small scale to large scale, and I then verge the attention to dark matter nature: dark matter candidates and their detection. I finally discuss some of the limits of the $\\Lambda$CDM model, with particular emphasis on the small scale problems of the paradigm.

  11. Galaxy Evolution by the Incompatibility between Dark Matter and Baryonic Matter

    OpenAIRE

    Ding-Yu Chung

    2014-01-01

    The paper derives the galaxy evolution by the non-interacting (incompatibility) between dark matter and baryonic matter in terms of the short-range separation between dark matter and baryonic matter, so dark matter cannot contact baryonic matter. In the conventional CDM (cold dark matter) model, dark matter and baryonic matter are interactive (compatible), so dark matter can contact baryonic matter. However, the conventional CDM model fails to account for the failure to...

  12. Baryon Dynamics, Dark Matter Substructure, and Galaxies

    CERN Document Server

    Weinberg, D H; Davé, R; Katz, N; Colombi, Stephane; Dav\\'e, Romeel; Katz, Neal; Weinberg, David H.

    2006-01-01

    By comparing a collisionless cosmological N-body simulation (DM) to an SPH simulation with the same initial conditions, we investigate the correspondence between the dark matter subhalos produced by collisionless dynamics and the galaxies produced by dissipative gas dynamics in a dark matter background. When galaxies in the SPH simulation become satellites in larger groups, they retain local dark matter concentrations (SPH subhalos) whose mass is typically five times their baryonic mass. The more massive subhalos of the SPH simulation have corresponding subhalos of similar mass and position in the DM simulation; at lower masses, there is fairly good correspondence, but some DM subhalos are in different spatial positions and some suffer tidal stripping or disruption. The halo occupation statistics of DM subhalos -- the mean number of subhalos, pairs, and triples as a function of host halo mass -- are very similar to those of SPH subhalos and SPH galaxies. Gravity of the dissipative baryon component amplifies t...

  13. The baryonic self similarity of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Alard, C., E-mail: alard@iap.fr [Institut d' Astrophysique de Paris, 98bis boulevard Arago, F-75014 Paris (France)

    2014-06-20

    The cosmological simulations indicates that dark matter halos have specific self-similar properties. However, the halo similarity is affected by the baryonic feedback. By using momentum-driven winds as a model to represent the baryon feedback, an equilibrium condition is derived which directly implies the emergence of a new type of similarity. The new self-similar solution has constant acceleration at a reference radius for both dark matter and baryons. This model receives strong support from the observations of galaxies. The new self-similar properties imply that the total acceleration at larger distances is scale-free, the transition between the dark matter and baryons dominated regime occurs at a constant acceleration, and the maximum amplitude of the velocity curve at larger distances is proportional to M {sup 1/4}. These results demonstrate that this self-similar model is consistent with the basics of modified Newtonian dynamics (MOND) phenomenology. In agreement with the observations, the coincidence between the self-similar model and MOND breaks at the scale of clusters of galaxies. Some numerical experiments show that the behavior of the density near the origin is closely approximated by a Einasto profile.

  14. Precombination Cloud Collapse and Baryonic Dark Matter

    Science.gov (United States)

    Hogan, Craig J.

    1993-01-01

    A simple spherical model of dense baryon clouds in the hot big bang 'strongly nonlinear primordial isocurvature baryon fluctuations' is reviewed and used to describe the dependence of cloud behavior on the model parameters, baryon mass, and initial over-density. Gravitational collapse of clouds before and during recombination is considered including radiation diffusion and trapping, remnant type and mass, and effects on linear large-scale fluctuation modes. Sufficiently dense clouds collapse early into black holes with a minimum mass of approx. 1 solar mass, which behave dynamically like collisionless cold dark matter. Clouds below a critical over-density, however, delay collapse until recombination, remaining until then dynamically coupled to the radiation like ordinary diffuse baryons, and possibly producing remnants of other kinds and lower mass. The mean density in either type of baryonic remnant is unconstrained by observed element abundances. However, mixed or unmixed spatial variations in abundance may survive in the diffuse baryon and produce observable departures from standard predictions.

  15. Dark Matter and the Baryon Asymmetry

    CERN Document Server

    Farrar, G R; Farrar, Glennys R.; Zaharijas, Gabrijela

    2006-01-01

    We present a mechanism to generate the baryon asymmetry of the Universe which preserves the net baryon number created in the Big Bang. If dark matter particles carry baryon number $B_X$, and $\\sigma^{\\rm annih}_{\\bar{X}} < \\sigma^{\\rm annih}_{X} $, the $\\bar{X}$'s freeze out at a higher temperature and have a larger relic density than $X$'s. If $m_X \\lsi 4.5 B_X $GeV and the annihilation cross sections differ by $\\mathcal{O}$(10%) or more, this type of scenario naturally explains the observed $\\Omega_{DM} \\approx 5 \\Omega_b$. Two concrete examples are given, one of which can be excluded on observational grounds.

  16. Shedding light on baryonic dark matter

    Science.gov (United States)

    Silk, Joseph

    1991-01-01

    Halo dark matter, if it is baryonic, may plausibly consist of compact stellar remnants. Jeans mass clouds containing 10 to the 6th to 10 to the 8th solar masses could have efficiently formed stars in the early universe and could plausibly have generated, for a suitably top-heavy stellar initial mass function, a high abundance of neutron stars as well as a small admixture of long-lived low mass stars. Within the resulting clusters of dark remnants, which eventually are tidally disrupted when halos eventually form, captures of neutron stars by nondegenerate stars resulted in formation of close binaries. These evolve to produce, by the present epoch, an observable X-ray signal associated with dark matter aggregations in galaxy cluster cores.

  17. 'Nonbaryonic' dark matter as baryonic colour superconductor

    International Nuclear Information System (INIS)

    We discuss a novel cold dark matter candidate which is formed from the ordinary quarks during the QCD phase transition when the axion domain wall undergoes an unchecked collapse due to the tension in the wall. If a large number of quarks is trapped inside the bulk of a closed axion domain wall, the collapse stops due to the internal Fermi pressure. In this case the system in the bulk, may reach the critical density when it undergoes a phase transition to a colour superconducting phase with the ground state being the quark condensate, similar to BCS theory. If this happens, the new state of matter representing the diquark condensate with a large baryon number B ∼ 1032 becomes a stable soliton-like configuration. Consequently, it may serve as a novel cold dark matter candidate

  18. Stealth Dark Matter: Dark scalar baryons through the Higgs portal

    CERN Document Server

    Appelquist, Thomas; Buchoff, Michael I; Fleming, George T; Jin, Xiao-Yong; Kiskis, Joe; Kribs, Graham D; Neil, Ethan T; Osborn, James C; Rebbi, Claudio; Rinaldi, Enrico; Schaich, David; Schroeder, Chris; Syritsyn, Sergey; Vranas, Pavlos; Weinberg, Evan; Witzel, Oliver

    2015-01-01

    We present a new model of "Stealth Dark Matter": a composite baryonic scalar of an $SU(N_D)$ strongly-coupled theory with even $N_D \\geq 4$. All mass scales are technically natural, and dark matter stability is automatic without imposing an additional discrete or global symmetry. Constituent fermions transform in vector-like representations of the electroweak group that permit both electroweak-breaking and electroweak-preserving mass terms. This gives a tunable coupling of stealth dark matter to the Higgs boson independent of the dark matter mass itself. We specialize to $SU(4)$, and investigate the constraints on the model from dark meson decay, electroweak precision measurements, basic collider limits, and spin-independent direct detection scattering through Higgs exchange. We exploit our earlier lattice simulations that determined the composite spectrum as well as the effective Higgs coupling of stealth dark matter in order to place bounds from direct detection, excluding constituent fermions with dominant...

  19. Non-baryonic dark matter: observational evidence and detection methods

    International Nuclear Information System (INIS)

    The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational information points to the existence of a non-baryonic component, contributing between around 20 and 40% of the critical mass density needed to make the universe geometrically flat on large scales. In addition, an even larger contribution from vacuum energy (or cosmological constant) is indicated by recent observations. To the theoretically favoured particle candidates for non-baryonic dark matter belong axions, supersymmetric particles, and of less importance, massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. Direct and indirect methods for detection of supersymmetric dark matter are described in some detail. Present experiments are just reaching the required sensitivity to discover or rule out some of these candidates, and major improvements are planned over the coming years. (author)

  20. Dark matter growth and baryon bias in an accelerating universe

    OpenAIRE

    Lee, Seokcheon

    2009-01-01

    We investigate the exact analytic solutions for the growths of the dark matter and the baryon in sub-horizon scale. The growth of the dark matter $\\delta_{\\DM}$ is related to that of the halos. Thus, the exact solution for the growth of the dark matter is important to obtain the proper properties of dark matter halos. However, the dark energy model dependence of $\\delta_{\\DM}$ is confused with the $\\delta_{\\DM}$ dependence on $\\Omega_{m}^{0}$. Thus, the careful investigation is necessary for ...

  1. Baryon Asymmetry, Dark Matter, and Density Perturbation from PBH

    CERN Document Server

    Fujita, Tomohiro; Harigaya, Keisuke; Matsuda, Ryo

    2014-01-01

    We investigate the consistency of a scenario in which the baryon asymmetry, dark matters, as well as the cosmic density perturbation are generated simultaneously through the evaporation of primordial black holes (PBHs). This scenario can explain the coincidence of the dark matter and the baryon density of the universe, and is free from the isocurvature perturbation problem. We show that this scenario predicts the masses of PBHs, right-handed neutrinos and dark matters, the Hubble scale during inflation, the non-gaussianity and the running of the spectral index. We also discuss the testability of the scenario by detecting high frequency gravitational waves from PBHs.

  2. Moduli induced cogenesis of baryon asymmetry and dark matter

    OpenAIRE

    Mansi Dhuria; Chandan Hati; Utpal Sarkar

    2016-01-01

    We study a cogenesis mechanism in which the observed baryon asymmetry of the universe and the dark matter abundance can be produced simultaneously at low reheating temperature without violating baryon number in the fundamental interactions. In particular, we consider a model which can be realized in the context of type IIB large volume string compactifications. The matter superfields in this model include additional pairs of color triplet and singlet superfields in addition to the Minimal Sup...

  3. Natural GeV Dark Matter and the Baryon-Dark Matter Coincidence Puzzle

    CERN Document Server

    Allahverdi, Rouzbeh

    2013-01-01

    We present a simple extension of the standard model that gives rise to baryogenesis a has a dark matter candidate of O(GeV) mass. A minimal set of new fields required for baryogenesis includes two O(TeV) colored scalars and a singlet fermion. The fermion also becomes a viable dark matter candidate when its is nearly degenerate in mass with the proton. Dark matter and baryon asymmetry are produced form the decay of heavy scalars, which can lead to a natural explanation of the baryon-dark matter coincidence problem. The dark matter candidate escapes direct and indirect detection, but can be probed at the LHC. The supersymmetric extension of this model is straightforward and leads to a multi-component dark matter scenario, which improves the direct and indirect detection prospects.

  4. On the separation between baryonic and dark matter: evidence for phantom dark matter?

    OpenAIRE

    Knebe, Alexander; Llinares, Claudio; Wu, Xufen; Zhao, HongSheng

    2009-01-01

    The recent years have seen combined measurements of X-ray and (weak) lensing contours for colliding galaxy clusters such as, for instance, the famous "Bullet" cluster. These observations have revealed offsets in the peaks of the baryonic and (dominant) gravitational matter component of order ~(100-200) kpc. Such discrepancies are difficult to explain using modified theories for gravity other than dark matter. Or are they not? Here we use the concept of "phantom dark matter" that is based upon...

  5. Role of baryons in unified dark matter models

    International Nuclear Information System (INIS)

    We discuss the importance of including baryons in analyses of unified dark matter scenarios, focusing on toy models involving a generalized Chaplygin gas. We determine observational constraints on this unified dark matter scenario coming from large-scale structure, type Ia supernovae and CMB data showing how this component can bring about a different behavior from the classical cold dark matter model with a cosmological constant and thus motivate further studies of this type of models. We also speculate on interesting new features which are likely to be important on nonlinear scales in this context

  6. Inside charged black holes. II. Baryons plus dark matter

    International Nuclear Information System (INIS)

    This is the second of two companion papers on the interior structure of self-similar accreting charged black holes. In the first paper, the black hole was allowed to accrete only a single fluid of charged baryons. In this second paper, the black hole is allowed to accrete in addition a neutral fluid of almost noninteracting dark matter. Relativistic streaming between outgoing baryons and ingoing dark matter leads to mass inflation near the inner horizon. When enough dark matter has been accreted that the center-of-mass frame near the inner horizon is ingoing, then mass inflation ceases and the fluid collapses to a central singularity. A null singularity does not form on the Cauchy horizon. Although the simultaneous presence of ingoing and outgoing fluids near the inner horizon is essential to mass inflation, reducing one or the other of the ingoing dark matter or outgoing baryonic streams to a trace relative to the other stream makes mass inflation more extreme, not the other way around as one might naively have expected. Consequently, if the dark matter has a finite cross section for being absorbed into the baryonic fluid, then the reduction of the amount of ingoing dark matter merely makes inflation more extreme, the interior mass exponentiating more rapidly and to a larger value before mass inflation ceases. However, if the dark matter absorption cross section is effectively infinite at high collision energy, so that the ingoing dark matter stream disappears completely, then the outgoing baryonic fluid can drop through the Cauchy horizon. In all cases, as the baryons and the dark matter voyage to their diverse fates inside the black hole, they only ever see a finite amount of time pass by in the outside universe. Thus the solutions do not depend on what happens in the infinite past or future. We discuss in some detail the physical mechanism that drives mass inflation. Although the gravitational force is inward, inward means opposite direction for ingoing and

  7. Constraining Dark Matter-Baryon Scattering with Linear Cosmology

    CERN Document Server

    Dvorkin, Cora; Kamionkowski, Marc

    2013-01-01

    We derive constraints on elastic scattering between baryons and dark matter using the cosmic microwave background (CMB) data from the Planck satellite and the Lyman-alpha forest data from the Sloan Digital Sky Survey. Elastic scattering allows baryons and dark matter to exchange momentum, affecting the dynamics of linear density perturbations in the early Universe. We derive constraints to scattering cross sections of the form sigma \\propto v^n, allowing for a wide range of velocity dependencies with n between -4 and 2. We improve and correct previous estimates where they exist, including velocity-independent cross section as well as dark matter millicharge and electromagnetic dipole moments. Lyman-alpha forest data dominates the constraints for n>-3, where the improvement over CMB data alone can be several orders of magnitude. Dark matter-baryon scattering cannot affect the halo mass function on mass scales M>10^{12} M_{solar}. Our results imply, model-independently, that a baryon in the halo of a galaxy lik...

  8. Moduli induced cogenesis of baryon asymmetry and dark matter

    Science.gov (United States)

    Dhuria, Mansi; Hati, Chandan; Sarkar, Utpal

    2016-05-01

    We study a cogenesis mechanism in which the observed baryon asymmetry of the universe and the dark matter abundance can be produced simultaneously at low reheating temperature without violating baryon number in the fundamental interactions. In particular, we consider a model which can be realized in the context of type IIB large volume string compactifications. The matter superfields in this model include additional pairs of color triplet and singlet superfields in addition to the Minimal Supersymmetric Standard Model (MSSM) superfields. Assuming that the mass of the additional singlet fermions is O (GeV) and of the color triplet fermions is O (TeV), we show that the modulus dominantly decays into the additional color triplet superfields. After soft supersymmetry (SUSY) breaking, the lightest eigenstate of scalar component of color triplet superfield further decays into fermionic component of singlet superfield and quarks without violating baryon number. Imposing discrete Z2 symmetry, it follows that the singlet fermion will not further decay into the SM particles and therefore it can be considered as a stable asymmetric dark matter (ADM) component. We find that the decay of the lightest eigenstate of scalar component of color triplet superfield gives the observed baryon asymmetry in the visible sector, an asymmetric dark matter component with the right abundance and naturally explains cosmic coincidence.

  9. On relating the genesis of cosmic baryons and dark matter

    International Nuclear Information System (INIS)

    The similar cosmological energy budgets in visible baryons and dark matter motivate one to consider a common origin for the generation of both. We outline the key features of scenarios that can accommodate a unified framework for the genesis of cosmic matter. In doing so, we provide a brief overview of some of the past and recent developments and discuss the main predictions of a number of models. (paper)

  10. Dark matter from unification of color and baryon number

    Science.gov (United States)

    Fornal, Bartosz; Tait, Tim M. P.

    2016-04-01

    We analyze a recently proposed extension of the Standard Model based on the S U (4 )×S U (2 )L×U (1 )X gauge group, in which baryon number is interpreted as the fourth color and dark matter emerges as a neutral partner of the ordinary quarks under S U (4 ). We show that under well-motivated minimal flavor-violating assumptions the particle spectrum contains a heavy dark matter candidate which is dominantly the partner of the right-handed top quark. Assuming a standard cosmology, the correct thermal relic density through freeze-out is obtained for dark matter masses around 2-3 TeV. We examine the constraints and future prospects for direct and indirect searches for dark matter. We also briefly discuss the LHC phenomenology, which is rich in top quark signatures, and investigate the prospects for discovery at a 100 TeV hadron collider.

  11. Helioseismology with long-range dark matter-baryon interactions

    DEFF Research Database (Denmark)

    Lopes, I.; Panci, Paolo; Silk, J.

    2014-01-01

    Assuming the existence of a primordial asymmetry in the dark sector, we study how long-range dark matter (DM)-baryon interactions, induced by the kinetic mixing of a new U(1) gauge boson and a photon, affect the evolution of the Sun and, in turn, the sound speed the profile obtained from...... agreement between the best solar model and the helioseismic data without being excluded by direct detection experiments. In particular, the LUX detector will soon be able to either constrain or confirm our best-fit solar model in the presence of a dark sector with long-range interactions that reconcile...

  12. The Role of Baryons in Unified Dark Matter Models

    CERN Document Server

    Beca, L M G; De Carvalho, J P M; Martins, C J

    2003-01-01

    We discuss the importance of including baryons in analyses of unified dark matter scenarios, focusing on toy models involving a generalized Chaplygin gas. We determine observational constraints on this unified dark matter scenario coming from large scale structure, type Ia Supernovae and CMB data showing how this component can bring about a different behaviour from classical $\\Lambda$CDM and thus motivate further studies of this type of models. We also speculate on interesting new features which are likely to be important on non-linear scales in this context.

  13. Continuum-Mediated Dark Matter-Baryon Scattering

    CERN Document Server

    Katz, Andrey; Sajjad, Aqil

    2016-01-01

    Many models of dark matter scattering with baryons may be treated either as a simple contact interaction or as the exchange of a light mediator particle. We study an alternative, in which a continuum of light mediator states may be exchanged. This could arise, for instance, from coupling to a sector which is approximately conformal at the relevant momentum transfer scale. In the non-relativistic effective theory of dark matter-baryon scattering, which is useful for parametrizing direct detection signals, the effect of such continuum mediators is to multiply the amplitude by a function of the momentum transfer q, which in the simplest case is just a power law. We develop the basic framework and study two examples: the case where the mediator is a scalar operator coupling to the Higgs portal (which turns out to be highly constrained) and the case of an antisymmetric tensor operator ${\\cal O}_{\\mu \

  14. Simultaneous Generation of WIMP Miracle-like Densities of Baryons and Dark Matter

    Science.gov (United States)

    McDonald, John

    2012-09-01

    The observed density of dark matter is of the magnitude expected for a thermal relic weakly-interacting massive particle (WIMP). In addition, the observed baryon density is within an order of magnitude of the dark matter density. This suggests that the baryon density is physically related to a typical thermal relic WIMP dark matter density. We present a model which simultaneously generates thermal relic WIMP-like densities for both baryons and dark matter by modifying a large initial baryon asymmetry. Production of unstable scalars carrying baryon number at the LHC would be a clear signature of the model.

  15. Generation of WIMP Miracle-like Densities of Baryons and Dark Matter

    CERN Document Server

    McDonald, John

    2012-01-01

    The observed density of dark matter is of the magnitude expected for a thermal relic weakly-interacting massive particle (WIMP). In addition, the observed baryon density is within an order of magnitude of the dark matter density. This suggests that the baryon density is physically related to a typical thermal relic WIMP dark matter density. We present a model which simultaneously generates thermal relic WIMP-like densities for both baryons and dark matter by modifying a large initial baryon asymmetry. Production of unstable scalars carrying baryon number at the LHC would be a clear signature of the model.

  16. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    Science.gov (United States)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  17. Baryon Asymmetry and Dark Matter Through the Vector-Like Portal

    OpenAIRE

    Fileviez Perez, P.; Wise, M.

    2013-01-01

    A possible connection between the cosmological baryon asymmetry, dark matter and vector-like fermions is investigated. In this scenario an asymmetry generated through baryogenesis or leptogenesis (in the vector-like matter sector) connects the baryon asymmetry to the dark matter density. We present explicit renormalizable models where this connection occurs. These models have asymmetric dark matter and a significant invisible Higgs decay width to dark matter particles is possible. We refer to...

  18. Continuum-mediated dark matter-baryon scattering

    Science.gov (United States)

    Katz, Andrey; Reece, Matthew; Sajjad, Aqil

    2016-06-01

    Many models of dark matter scattering with baryons may be treated either as a simple contact interaction or as the exchange of a light mediator particle. We study an alternative, in which a continuum of light mediator states may be exchanged. This could arise, for instance, from coupling to a sector which is approximately conformal at the relevant momentum transfer scale. In the non-relativistic effective theory of dark matter-baryon scattering, which is useful for parametrizing direct detection signals, the effect of such continuum mediators is to multiply the amplitude by a function of the momentum transfer q, which in the simplest case is just a power law. We develop the basic framework and study two examples: the case where the mediator is a scalar operator coupling to the Higgs portal (which turns out to be highly constrained) and the case of an antisymmetric tensor operator Oμν that mixes with the hypercharge field strength and couples to dark matter tensor currents, which has an interesting viable parameter space. We describe the effect of such mediators on the cross sections and recoil energy spectra that could be observed in direct detection.

  19. Explaining the Dark Energy, Baryon and Dark Matter Coincidence via Domain-Dependent Random Densities

    CERN Document Server

    McDonald, John

    2013-01-01

    The dark energy, dark matter and baryon densities in the Universe are observed to be similar, with a factor of no more than 20 between the largest and smallest densities. We show that this coincidence can be understood via superhorizon domains of randomly varying densities when the baryon density at initial collapse of galaxy-forming perturbations is determined by anthropic selection. The baryon and dark matter densities are assumed to be dependent on random variables \\theta_{d} and \\theta_{b} according to \\rho_{dm} ~ \\theta_{d}^{\\alpha} and \\rho_{b} ~ \\theta_{b}^{\\beta}, while the effectively constant dark energy density is dependent upon a random variable \\phi_{Q} according to \\rho_{Q} ~ \\phi_{Q}^{n}. The ratio of the baryon density to the dark energy density at initial collapse, r_{Q}, and the baryon-to-dark matter ratio, r, are then determined purely statistically, with no dependence on the anthropically-preferred baryon density. We compute the probability distribution for r_{Q} and r and show that the ob...

  20. Some Consequences of the Baryonic Dark Matter Population

    CERN Document Server

    Schild, R E

    2004-01-01

    Microlensed double-image quasars have sent a consistent message that the baryonic dark matter consists of a population of free-roaming planet mass objects, as summarized previously. These were previously predicted to have formed at the time of recombination, 300,000 years after the Big Bang, whence they collapsed on a Kelvin Helmholz time scale. Today they are glimpsed as the cometary knots in planetary nebulae. But they probably also nucleate the mysterious Lyman-alpha clouds and cause a reduction in the transparency of the universe to distant quasars and supernovae.

  1. Theories relating baryon asymmetry and dark matter: a Mini review

    Directory of Open Access Journals (Sweden)

    Stefano eMorisi

    2014-01-01

    Full Text Available The nature of dark matter and the origin of the baryon asymmetry are two of the deepest mysteries of modern particle physics. In the absence of hints regarding a possible solution to these mysteries, many approaches have been developed to tackle them simultaneously { leading to very diverse and rich models}. We give a short review where we describe the general features of some of these models and an overview on the general problem. We also propose a diagrammatic notation to label the different models.

  2. Entropy, baryon asymmetry and dark matter from heavy neutrino decays

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Schmitz, K.; Vertongen, G.

    2011-04-15

    The origin of the hot phase of the early universe remains so far an unsolved puzzle. A viable option is entropy production through the decays of heavy Majorana neutrinos whose lifetimes determine the initial temperature. We show that baryogenesis and the production of dark matter are natural by-products of this mechanism. As is well known, the cosmological baryon asymmetry can be accounted for by lepto- genesis for characteristic neutrino mass parameters. We nd that thermal gravitino production then automatically yields the observed amount of dark matter, for the gravitino as the lightest superparticle and typical gluino masses. As an example, we consider the production of heavy Majorana neutrinos in the course of tachyonic preheating associated with spontaneous B-L breaking. A quantitative analysis leads to contraints on the superparticle masses in terms of neutrino masses: For a light neutrino mass of 10{sup -5} eV the gravitino mass can be as small as 200 MeV, whereas a lower neutrino mass bound of 0.01 eV implies a lower bound of 9 GeV on the gravitino mass. The measurement of a light neutrino mass of 0.1 eV would rule out heavy neutrino decays as the origin of entropy, visible and dark matter. (orig.)

  3. The joint evolution of baryons and dark matter haloes

    CERN Document Server

    Pedrosa, Susana E; Scannapieco, Cecilia

    2009-01-01

    We have studied the dark matter (DM) distribution in a approx 10^12 h^-1 M_sun mass halo extracted from a simulation consistent with the concordance cosmology, where the physics regulating the transformation of gas into stars was allowed to change producing galaxies with different morphologies. The presence of baryons produces the concentration of the DM halo with respect to its corresponding dissipationless run, but we found that this response does not only depend on the amount of baryons gathered in the central region but also on the way they have been assembled. DM and baryons affect each other in a complex way so the formation history of a galaxy plays an important role on its final total mass distribution. The Supernova (SN) feedback regulates the star formation and triggers galactic outflows not only in the central galaxy but also in their satellites. Our results suggest that, as the effects of SN feedback get stronger, satellites get less massive and can even be more easily disrupted by dynamical frict...

  4. Forming supermassive black holes by accreting dark and baryon matter

    CERN Document Server

    Hu, J; Lou, Y Q; Zhang, S; Hu, Jian; Shen, Yue; Lou, Yu-Qing; Zhang, Shuangnan

    2006-01-01

    Given a large-scale mixture of self-interacting dark matter (SIDM) particles and baryon matter distributed in the early Universe, we advance here a two-phase accretion scenario for forming supermassive black holes (SMBHs) with masses around $\\sim 10^9 M_{\\odot}$ at high redshifts $z (\\gsim 6)$. The first phase is conceived to involve a rapid quasi-spherical and quasi-steady Bondi accretion of mainly SIDM particles embedded with baryon matter onto seed black holes (BHs) created at redshifts $z\\lsim 30$ by the first generation of massive Population III stars; this earlier phase rapidly gives birth to significantly enlarged seed BH masses of $M_{\\hbox{\\tiny BH},t_1}\\backsimeq 1.4\\times 10^6\\ M_\\odot \\sigma_0/(1\\hbox{cm}^2\\hbox{g}^{-1})(C_s/30\\hbox{km s}^{-1})^4$ during $z\\sim 20-15$, where $\\sigma_0$ is the cross section per unit mass of SIDM particles and $C_s$ is the velocity dispersion in the SIDM halo referred to as an effective "sound speed". The second phase of BH mass growth is envisaged to proceed primar...

  5. Helioseismology with long-range dark matter-baryon interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Ilídio [Centro Multidisciplinar de Astrofísica, Instituto Superior Técnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Panci, Paolo [CP3-Origins and DIAS, University of Southern Denmark, DK-5230 Odense (Denmark); Silk, Joseph, E-mail: ilidio.lopes@tecnico.ulisboa.pt, E-mail: panci@iap.fr, E-mail: silk@astro.ox.ac.uk [Institut d' Astrophysique, UMR 7095 CNRS, Université Pierre et Marie Curie, 98bis Blvd Arago, F-75014 Paris (France)

    2014-11-10

    Assuming the existence of a primordial asymmetry in the dark sector, we study how long-range dark matter (DM)-baryon interactions, induced by the kinetic mixing of a new U(1) gauge boson and a photon, affect the evolution of the Sun and, in turn, the sound speed the profile obtained from helioseismology. Thanks to the explicit dependence on the exchanged momenta in the differential cross section (Rutherford-like scattering), we find that DM particles with a mass of ∼10 GeV, kinetic mixing parameter of the order of 10{sup –9}, and a mediator with a mass smaller than a few MeV improve the agreement between the best solar model and the helioseismic data without being excluded by direct detection experiments. In particular, the LUX detector will soon be able to either constrain or confirm our best-fit solar model in the presence of a dark sector with long-range interactions that reconcile helioseismology with thermal neutrino results.

  6. Dogs that Don't Bark (The Tale of Baryonic Dark Matter in Galaxies)

    CERN Document Server

    Evans, N W

    2002-01-01

    Fifteen years or so ago, it was commonly argued; ``If we want to believe the observations rather than our prejudice, we should take as our best bet that dark haloes are baryonic.'' Such a viewpoint is not often heard today. This change-of-mind has been enforced upon us largely by the microlensing experiments. Particle dark matter differs from (most types of) baryonic dark matter in that it does not produce microlensing events. The familiar parade of baryonic candidates has now been whittled down, and perhaps only one remains as a possible substantial contributor to the dark matter in the Galaxy's halo. This review assesses the distribution of missing matter in the Galaxy, the likely baryonic dark matter suspects, the evidence from microlensing and from the halo white dwarf searches.

  7. Baryonic impact on the dark matter distribution in Milky Way-sized galaxies and their satellites

    Science.gov (United States)

    Zhu, Qirong; Marinacci, Federico; Maji, Moupiya; Li, Yuexing; Springel, Volker; Hernquist, Lars

    2016-05-01

    We study the impact of baryons on the distribution of dark matter in a Milky Way-sized halo by comparing a high-resolution, moving mesh cosmological simulation with its dark matter-only counterpart. We identify three main processes related to baryons - adiabatic contraction, tidal disruption, and reionization - which jointly shape the dark matter distribution in both the main halo and its subhaloes. The relative effect of each baryonic process depends strongly on the subhalo mass. For massive subhaloes with maximum circular velocity vmax > 35 km s-1, adiabatic contraction increases the dark matter concentration, making these haloes less susceptible to tidal disruption. For low-mass subhaloes with vmax dark matter cores in dwarf galaxies, unlike previous studies that employed bursty feedback-driven outflows. The substantial impact of baryons on the abundance and internal structure of subhaloes suggests that galaxy formation and evolution models based on N-body simulations should include these physical processes as major components.

  8. Dark matter, lepton and baryon number, and left-right symmetric theories

    Science.gov (United States)

    Patra, Sudhanwa

    2016-05-01

    A lepto-baryonic left-right symmetric theory is considered along with pointing out stable dark matter candidates whose stability is ensured automatically where leptons and baryons are defined as local gauge symmetries. These theories are generally anomalous, and the possible gauge anomaly free solutions for these theories are presented. It is found that the neutral component of fermion triplets can be a viable dark matter candidate originally introduced for gauge anomaly cancellation. The other dark matter possibilities within this lepto-baryonic left-right symmetric theory are also presented.

  9. The electroweak axion, dark energy, inflation and baryonic matter

    International Nuclear Information System (INIS)

    In a previous paper [1], the standard model was generalized to include an electroweak axion which carries baryon plus lepton number, B + L. It was shown that such a model naturally gives the observed value of the dark energy, if the scale of explicit baryon number violation A was chosen to be of the order of the Planck mass. In this paper, we consider the effect of the modulus of the axion field. Such a field must condense in order to generate the standard Goldstone boson associated with the phase of the axion field. This condensation breaks baryon number. We argue that this modulus might be associated with inflation. If an additional B − L violating scalar is introduced with a mass similar to that of the modulus of the axion field, we argue that decays of particles associated with this field might generate an acceptable baryon asymmetry

  10. The angular momentum of baryons and dark matter halos revisited

    OpenAIRE

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive mesh refinement, we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole....

  11. Baryon number asymmetry and dark matter in the neutrino mass model with an inert doublet

    OpenAIRE

    Kashiwase, Shoichi; Suematsu, Daijiro

    2012-01-01

    The radiative neutrino mass model with an inert doublet scalar has been considered as a promising candidate which can explain neutrino masses, dark matter abundance and baryon number asymmetry if dark matter is identified with the lightest neutral component of the inert doublet. We reexamine these properties by imposing all the data of the neutrino oscillation, which are recently suggested by the reactor experiments. We find that the sufficient baryon number asymmetry seems not to be easily g...

  12. Baryon Asymmetry and Dark Matter Through the Vector-Like Portal

    CERN Document Server

    Perez, Pavel Fileviez

    2013-01-01

    A possible connection between the cosmological baryon asymmetry, dark matter and vector-like fermions is investigated. In this scenario an asymmetry generated through baryogenesis or leptogenesis (in the vector-like matter sector) connects the baryon asymmetry to the dark matter density. We present explicit renormalizable models where this connection occurs. These models have asymmetric dark matter and a significant invisible Higgs decay width to dark matter particles is possible. We refer to this type of scenario as the vector-like portal. In some asymmetric dark matter models there are potential naturalness issues for the low energy effective theory. We address that issue in the models we consider by starting with a Lagrangian that is the most general renormalizable one consistent with the gauge (and discrete) symmetries and showing the low energy effective theory automatically has the required form as a consequence of the symmetries of the full theory. We show that the mass of the dark matter candidate is ...

  13. Simultaneous Generation of WIMP Miracle-like Densities of Baryons and Dark Matter

    CERN Document Server

    McDonald, John

    2011-01-01

    The observed density of dark matter is of the magnitude expected for a thermal relic weakly-interacting massive particle (WIMP). In addition, the observed baryon density is within an order of magnitude of the dark matter density. This suggests that the baryon density is physically related to a typical thermal relic WIMP dark matter density. We present a model which simultaneously generates thermal relic WIMP-like densities for both baryons and dark matter by modifying a large initial baryon asymmetry. Dark matter is due to O(100) GeV gauge singlet scalars produced in the annihilation of the O(TeV) coloured scalars which is responsible for the final thermal WIMP-like baryon asymmetry. The requirement of no baryon washout implies that there are two gauge singlet scalars. The low temperature transfer of the asymmetry to conventional baryons can be understood if the long-lived O(TeV) coloured scalars have large hypercharge, |Y| > 4/3. Production of such scalars at the LHC would be a clear signature of the model.

  14. Dark Matter

    OpenAIRE

    Einasto, Jaan

    2013-01-01

    I give a review of the development of the concept of dark matter. The dark matter story passed through several stages from a minor observational puzzle to a major challenge for theory of elementary particles. Modern data suggest that dark matter is the dominant matter component in the Universe, and that it consists of some unknown non-baryonic particles. Dark matter is the dominant matter component in the Universe, thus properties of dark matter particles determine the structure of the cosmic...

  15. Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter

    OpenAIRE

    Dabringhausen, J.; Kroupa, P.; Famaey, B.; Fellhauer, M.

    2016-01-01

    Assuming virial equilibrium and Newtonian dynamics, low-mass early-type galaxies have larger velocity dispersions than expected from the amount of baryons they contain. The conventional interpretation of this finding is that their dynamics is dominated by non-baryonic matter. However, there is also strong evidence that many low-mass early-type galaxies formed as tidal dwarf galaxies, which would contain almost no dark matter. Using an extensive catalogue of early-type galaxies, we therefore d...

  16. Dark Matter

    OpenAIRE

    Bahcall, Neta

    1996-01-01

    Observations in the optical, in X-rays, and gravitational lensing of galaxies, clusters of galaxies, and large-scale structure are beginning to provide clues to the dark matter problem. I review the impact of these observations on some of the main questions relating to dark matter: How much dark matter is there? Where is it located? What is the nature of the dark matter? and what is the amount of baryonic dark matter.

  17. The angular momentum of baryons and dark matter halos revisited

    CERN Document Server

    Kimm, Taysun; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive mesh refinement, we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r=0.1rvir. In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/rvir>0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its ...

  18. Sharing but not Caring: Dark Matter and the Baryon Asymmetry of the Universe

    OpenAIRE

    Bernal, Nicolás; Fong, Chee Sheng; Fonseca, Nayara

    2016-01-01

    We consider scenarios where Dark Matter (DM) particles carry baryon and/or lepton numbers, which can be defined if there exist operators connecting the dark to the visible sector. As a result, the DM fields become intimately linked to the Standard Model (SM) ones and can be maximally asymmetric just like the ordinary matter. In particular, we discuss minimal scenarios where the DM is a complex scalar or a Dirac fermion coupled to operators with nonzero baryon and/or lepton numbers, and that c...

  19. Effects of baryons on the dark matter distribution in cosmological hydrodynamical simulations

    Science.gov (United States)

    Schaller, Matthieu

    2015-09-01

    Simulations including solely dark matter performed over the last three decades have delivered an accurate and robust description of the cosmic web and dark matter structures. With the advent of more precise cosmological probes, planned and ongoing, and dark matter detection experiments, this numerical modelling has to be improved to incorporate the complex non-linear and energetic processes taking place during galaxy formation. We use the ``Evolution and Assembly of GaLaxies and their Environment'' (EAGLE) suite of cosmological simulations to investigate the effects of baryons and astrophysical processes on the underlying dark matter distribution. Many effects are expected and we investigate (i): the modification of the profile of halos from the Navarro-Frenk-White profile shape found in collisionless simulations, including the changes in the dark matter profiles themselves, (ii) the changes of the inner density profiles of rich clusters, where observations have suggested a deviation from the standard cold dark matter paradigm, (iii) the offset created by astrophysical process between the centre of galaxies and the centre of the dark matter halo in which they reside and, (iv) the changes in the shape of the dark matter profile due to baryons in the centre of Milky Way halos and the impact these changes have on the morphology of the annihilation signal that could be observed as an indirect proof of the existence of dark matter. In all cases we find that the baryons play a significant role and change the results found in collisionless simulations dramatically. This highlights the need for more simulations like EAGLE to better understand and analyse future cosmology surveys. We also conduct a thorough study of the hydrodynamics solver parameters used in these simulations, assess their impact on the simulated galaxy population and show how robust some of the EAGLE results are against such variations.

  20. Dark matter

    OpenAIRE

    Einasto, J.

    2011-01-01

    I give a review of the development of the concept of dark matter. The dark matter story passed through several stages from a minor observational puzzle to a major challenge for theory of elementary particles. Modern data suggest that dark matter is the dominant matter component in the Universe, and that it consists of some unknown non-baryonic particles. Properties of dark matter particles determine the structure of the cosmic web.

  1. Dark matters

    Science.gov (United States)

    Steigman, Gary

    The observational evidence for dark matter in the universe is reviewed. Constraints on the baryon density from primordial nucleosynthesis are presented and compared to the dynamical estimates of the mass on various scales. Baryons can account for the observed luminous mass as well as some, perhaps most, of the 'observed' dark mass. However if, as inflation/naturalness suggest, the total density of the universe is equal to the critical density, then nonbaryonic dark matter is required. The assets and liabilities of, as well as the candidates for, hot and cold dark matter are outlined. At present, there is no completely satisfactory candidate for nonbaryonic dark matter.

  2. Impact of baryon physics on dark matter structures: a detailed simulation study of halo density profiles

    CERN Document Server

    Duffy, Alan R; Kay, Scott T; Vecchia, Claudio Dalla; Battye, Richard A; Booth, C M

    2010-01-01

    The back-reaction of baryons on the dark matter halo density profile is of great interest, not least because it is an important systematic uncertainty when attempting to detect the dark matter. Here, we draw on a large suite of high resolution cosmological hydrodynamical simulations, to systematically investigate this process and its dependence on the baryonic physics associated with galaxy formation. The inclusion of baryons results in significantly more concentrated density profiles if radiative cooling is efficient and feedback is weak. The dark matter halo concentration can in that case increase by as much as 30 (10) per cent on galaxy (cluster) scales. The most significant effects occur in galaxies at high redshift, where there is a strong anti-correlation between the baryon fraction in the halo centre and the inner slope of both the total and the dark matter density profiles. If feedback is weak, isothermal inner profiles form, in agreement with observations of massive, early-type galaxies. However, we ...

  3. Dark Matter and Baryon Asymmetry production from out-of-equilibrium decays of Supersymmetric states

    CERN Document Server

    Arcadi, Giorgio

    2015-01-01

    We will review the main aspects of a mechanism for the contemporary generation of the baryon and Dark Matter abundances from the out-of-equilibrium decay of a Wimp-like mother particle and briefly discuss a concrete realization in a Supersymmetric scenario.

  4. Dark Matter and Baryon Asymmetry production from out-of-equilibrium decays of Supersymmetric states

    Science.gov (United States)

    Arcadi, Giorgio

    2016-02-01

    We will review the main aspects of a mechanism for the contemporary generation of the baryon and Dark Matter abundances from the out-of-equilibrium decay of a WIMP-like mother particle and briefly discuss a concrete realization in a Supersymmetric scenario.

  5. Revisiting the gravitino dark matter and baryon asymmetry from Q-ball decay in gauge mediation

    Energy Technology Data Exchange (ETDEWEB)

    Kasuya, Shinta, E-mail: kasuya@kanagawa-u.ac.jp [Department of Mathematics and Physics, Kanagawa University, Kanagawa 259-1293 (Japan); Max-Planck-Institut für Kernphysik, PO Box 103980, 69029 Heidelberg (Germany); Kawasaki, Masahiro [Institute for Cosmic Ray Research, the University of Tokyo, Chiba 277-8582 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (WPI), Todai Institutes for Advanced Study, the University of Tokyo, Chiba 277-8582 (Japan); Yamada, Masaki [Institute for Cosmic Ray Research, the University of Tokyo, Chiba 277-8582 (Japan)

    2013-10-07

    We reconsider the Q-ball decay and reinvestigate the scenario that the amount of the baryons and the gravitino dark matter is naturally explained by the decay of the Q balls in the gauge-mediated SUSY breaking. We refine the decay rates into baryons, NLSPs, and gravitinos, and estimate their branching ratios based on the consideration of Pauli blocking. We obtain a smaller branching into gravitinos than the previous estimate, and the NLSPs are more produced by the Q-ball decay. However, the efficient annihilations of NLSPs occur afterward so that their abundance does not spoil the successful BBN and they only produce negligible amount of the gravitinos to the dark matter density by their decay. In this way, we find that the scenario with the direct production of the gravitino dark matter from the Q-ball decay works naturally.

  6. Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter

    Science.gov (United States)

    Dabringhausen, J.; Kroupa, P.; Famaey, B.; Fellhauer, M.

    2016-08-01

    Assuming virial equilibrium and Newtonian dynamics, low-mass early-type galaxies have larger velocity dispersions than expected from the amount of baryons they contain. The conventional interpretation of this finding is that their dynamics is dominated by non-baryonic matter. However, there is also strong evidence that many low-mass early-type galaxies formed as tidal dwarf galaxies, which would contain almost no dark matter. Using an extensive catalogue of early-type galaxies, we therefore discuss how the internal dynamics of early-type galaxies in general can be understood by replacing the assumption of non-baryonic dark matter with two alternative assumptions. The first assumption is that Milgromian dynamics (i.e., MOND) is valid, which changes the effective gravitational force in the weak-field limit. The second assumption is that binary stars affect the observed line-of-sight velocity dispersions. Some moderate discrepancies between observed and predicted velocity dispersions remain also when these effects are implemented. Nevertheless, the observed velocity dispersions in early-type galaxies can then easily be explained without invoking the presence of non-baryonic dark matter in them, but with already documented variations of the galaxy-wide stellar initial mass function and non-equilibrium dynamics in some of the low-mass early-type galaxies.

  7. Neutrino masses, dark matter and baryon asymmetry of the Universe

    CERN Document Server

    Ahriche, Amine

    2014-01-01

    In this work, we try to explain the neutrino mass and mixing data radiatively at three-loop by extending the standard model (SM) with two charged singlet scalars and three right handed (RH) neutrinos. Here, the lightest RH neutrino is a dark matter candidate that gives a relic density in agreement with the recent Planck data, the model can be consistent with the neutrino oscillation data, lepton flavor violating processes, the electroweak phase transition can be strongly first order; and the charged scalars may enhance the branching ratio $h\\rightarrow\\gamma\\gamma$, where as $h\\rightarrow\\gamma Z$ get can get few percent suppression. We also discuss the phenomenological implications of the RH neutrinos at the collider.

  8. Was ordinary matter synthesised from mirror matter? An attempt to explain why $\\Omega_{Baryon} \\approx 0.2\\Omega_{Dark}$

    OpenAIRE

    Foot, R.; Volkas, R. R.

    2003-01-01

    The cosmological dust has begun to settle. A likely picture is a universe comprised (predominantly) of three components: ordinary baryons ($\\Omega_B \\approx 0.05$), non-baryonic dark matter ($\\Omega_{Dark} \\approx 0.22$) and dark energy ($\\Omega_{\\Lambda} \\approx 0.7$). We suggest that the observed similarity of the abundances of ordinary baryons and non-baryonic dark matter ($\\Omega_{B}/\\Omega_{Dark} \\approx 0.20$) hints at an underlying similarity between the fundamental properties of ordin...

  9. The impact of baryons on the direct detection of dark matter

    CERN Document Server

    Kelso, Chris; Valluri, Monica; Freese, Katherine; Stinson, Gregory S; Bailin, Jeremy

    2016-01-01

    The spatial and velocity distributions of dark matter particles in the Milky Way Halo affect the signals expected to be observed in searches for dark matter. Results from direct detection experiments are often analyzed assuming a simple isothermal distribution of dark matter, the Standard Halo Model (SHM). Yet there has been skepticism regarding the validity of this simple model due to the complicated gravitational collapse and merger history of actual galaxies. In this paper we compare the SHM to the results of cosmological hydrodynamical simulations of galaxy formation to investigate whether or not the SHM is a good representation of the true WIMP distribution in the analysis of direct detection data. We examine two Milky Way-like galaxies from the MaGICC cosmological simulations (a) with dark matter only and (b) with baryonic physics included. The inclusion of baryons drives the shape of the DM halo to become more spherical and makes the velocity distribution of dark matter particles less anisotropic espec...

  10. Dwarf galaxies in CDM and SIDM with baryons: observational probes of the nature of dark matter

    CERN Document Server

    Vogelsberger, Mark; Simpson, Christine; Jenkins, Adrian

    2014-01-01

    We present the first cosmological simulations of dwarf galaxies, which include dark matter self-interactions and baryons. We study two dwarf galaxies within cold dark matter, and four different elastic self-interacting scenarios with constant and velocity-dependent cross sections, motivated by a new force in the hidden dark matter sector. Our highest resolution simulation has a baryonic mass resolution of $1.8\\times 10^2\\,{\\rm M}_\\odot$ and a gravitational softening length of $34\\,{\\rm pc}$ at $z=0$. In this first study we focus on the regime of mostly isolated dwarf galaxies with halo masses $\\sim10^{10}\\,{\\rm M}_\\odot$ where dark matter dynamically dominates even at sub-kpc scales. We find that while the global properties of galaxies of this scale are minimally affected by allowed self-interactions, their internal structures change significantly if the cross section is large enough within the inner sub-kpc region. In these dark-matter-dominated systems, self-scattering ties the shape of the stellar distribu...

  11. A TeV scale model for neutrino mass, dark matter and baryon asymmetry

    OpenAIRE

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2009-01-01

    We discuss a TeV scale model which would explain neutrino oscillation, dark matter, and baryon asymmetry of the Universe simultaneously by the dynamics of the extended Higgs sector and TeV-scale right-handed neutrinos with imposed an exact $Z_2$ symmetry. Tiny neutrino masses are generated at the three loop level, a singlet scalar field is a candidate of dark matter, and a strong first order phase transition is realized for successful electroweak baryogenesis. The model provides various discr...

  12. An extended Higgs sector for neutrino mass, dark matter and baryon asymmetry

    OpenAIRE

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2009-01-01

    In this talk, we discuss a TeV scale model which would explain neutrino oscillation, dark matter, and baryon asymmetry of the Universe simultaneously by the dynamics of the extended Higgs sector and TeV-scale right-handed neutrinos. By the imposed exact $Z_2$ symmetry, tiny neutrino masses are generated at the three loop level, and the stability of the dark matter candidate, an additional singlet scalar field, is guaranteed. The extra Higgs doublet is introduced not only for neutrino masses b...

  13. Cosmological phase transition, baryon asymmetry and dark matter Q-balls

    CERN Document Server

    Krylov, E; Rubakov, V

    2013-01-01

    We consider a mechanism of dark matter production in the course of first order phase transition. We assume that there is an asymmetry between X- and anti-X-particles of dark sector. In particular, it may be related to the baryon asymmetry. We also assume that the phase transition is so strongly first order, that X-particles do not permeate into the new phase. In this case, as the bubbles of old phase collapse, X-particles are packed into Q-balls with huge mass defect. These Q-balls compose the present dark matter. We find that the required present dark matter density is obtained for the energy scale of the theory in the ballpark of 1-10 TeV. As an example we consider a theory with effective potential of one-loop motivated form.

  14. The baryonic Tully-Fisher Relation predicted by cold dark matter cosmogony

    CERN Document Server

    Desmond, Harry

    2012-01-01

    The baryonic Tully-Fisher Relation (TFR) is a tight relationship observed between baryonic mass and rotational velocity in spiral galaxies. Providing a theoretical basis for the TFR in the Cold Dark Matter (CDM) paradigm has proved problematic: simple calculations suggest too low a slope and too high a scatter. This paper aims to develop a rigorous prediction for the relation in the context of CDM by accounting for all relevant TFR-independent effects observed in numerical simulations of dark matter haloes, including their expected scatter. It is demonstrated that consistent treatment of these effects goes a large way towards reconciling the CDM prediction with the data; the normalisation becomes almost perfect, athough the slope remains somewhat too low. The predicted scatter is indeed too large, but may be reduced to near that of the data by accouting for observational selection effects.

  15. Asymmetric Dark Matter

    OpenAIRE

    Kaplan, David E.; Luty, Markus A.; Zurek, Kathryn M.

    2009-01-01

    We consider a simple class of models in which the relic density of dark matter is determined by the baryon asymmetry of the universe. In these models a $B - L$ asymmetry generated at high temperatures is transfered to the dark matter, which is charged under $B - L$. The interactions that transfer the asymmetry decouple at temperatures above the dark matter mass, freezing in a dark matter asymmetry of order the baryon asymmetry. This explains the observed relation between the baryon and dark m...

  16. Understanding the internal dynamics of elliptical galaxies without non-baryonic dark matter

    CERN Document Server

    Dabringhausen, J; Famaey, B; Fellhauer, M

    2016-01-01

    Assuming virial equilibrium and Newtonian dynamics, low-mass early-type galaxies have larger velocity dispersions than expected from the amount of baryons they contain. The conventional interpretation of this finding is that their dynamics is dominated by non-baryonic matter. However, there is also strong evidence that many low-mass early-type galaxies formed as tidal dwarf galaxies, which would contain almost no dark matter. Using an extensive catalogue of early-type galaxies, we therefore discuss how the internal dynamics of early-type galaxies in general can be understood by replacing the assumption of non-baryonic dark matter with two alternative assumptions. The first assumption is that Milgromian dynamics (i.e., MOND) is valid, which changes the effective gravitational force in the weak-field limit. The second assumption is that binary stars affect the observed line-of-sight velocity dispersions. Some moderate discrepancies between observed and predicted velocity dispersions remain also when these effec...

  17. Constraints on the interactions between dark matter and baryons from the x-ray quantum calorimetry experiment

    International Nuclear Information System (INIS)

    Although the rocket-based x-ray quantum calorimetry (XQC) experiment was designed for x-ray spectroscopy, the minimal shielding of its calorimeters, its low atmospheric overburden, and its low-threshold detectors make it among the most sensitive instruments for detecting or constraining strong interactions between dark matter particles and baryons. We use Monte Carlo simulations to obtain the precise limits the XQC experiment places on spin-independent interactions between dark matter and baryons, improving upon earlier analytical estimates. We find that the XQC experiment rules out a wide range of nucleon-scattering cross sections centered around 1 b for dark matter particles with masses between 0.01 and 105 GeV. Our analysis also provides new constraints on cases where only a fraction of the dark matter strongly interacts with baryons

  18. Dark matter annihilation in the Milky Way galaxy: Effects of baryonic compression

    International Nuclear Information System (INIS)

    If the dark matter (DM), which is considered to constitute most of the mass of galaxies, is made of supersymmetric particles, the central region of our Galaxy should emit γ rays produced by their annihilation. We use detailed models of the Milky Way to make accurate estimates of continuum γ-ray fluxes. We argue that the most important effect, which was previously neglected, is the compression of the dark matter due to the infall of baryons to the galactic center: it boosts the expected signal by a factor 1000. To illustrate this effect, we computed the expected γ fluxes in the minimal supergravity scenario. Our models predict that the signal could be detected at high confidence levels by imaging atmospheric Cerenkov telescopes assuming that neutralinos make up most of the DM in the Universe

  19. Effect of supersonic relative motion between baryons and dark matter on collapsed objects

    CERN Document Server

    Asaba, Shinsuke; Tashiro, Hiroyuki

    2015-01-01

    The first star formation and the Epoch of Reionization are paid great attention to as main targets of planned large radio interferometries (e.g. Square Kilometre Array). Recently, it is claimed that the supersonic relative velocity between baryons and cold dark matter can suppress the abundance of the first stars and impact the cosmological reionization process. Therefore, in order to compare observed results with theoretical predictions it is important to examine the effect of the supersonic relative motion on the small-scale structure formation. In this paper, we investigate the effect on the nonlinear structure formation in the context of the spherical collapse model. We show the evolution of the dark matter sphere with the relative velocity by both using N-body simulations and numerical calculations of the equation of motion for the dark matter mass shell. The effects of the relative motions in the spherical collapse model appear as the delay of the collapse time of dark matter halos and the decrease of t...

  20. Baryonic Conversion Tree: The global assembly of stars and dark matter in galaxies from the SDSS

    CERN Document Server

    Jiménez, R; Heavens, A; Verde, L

    2004-01-01

    Using the spectroscopic sample of the SDSS DR1 we measure how gas was transformed into stars as a function of time and stellar mass: the baryonic conversion tree (BCT). There is a clear correlation between early star formation activity and present-day stellar mass: the more massive galaxies have converted about 80% of their baryons into stars at z>1, while for the less massive ones the value is only about 20%. In other words, while the dark matter halo formation is hierarchical (small objects form first and large objects later), the formation of their stellar component is anti-hierarchical (large galaxies are older in this respect than small ones). By comparing the BCT to the dark matter merger tree, we find indications that star formation efficiency at z>1 had to be high (~30%) in galaxies with present-day stellar mass larger than 2 x 10^{11}. Therefore, the LCDM paradigm can accommodate a large number of red objects; it is the high efficiency in the conversion from gas to stars that needs to be explained. O...

  1. Sharing but not caring: dark matter and the baryon asymmetry of the universe

    Science.gov (United States)

    Bernal, Nicolás; Fong, Chee Sheng; Fonseca, Nayara

    2016-09-01

    We consider scenarios where Dark Matter (DM) particles carry baryon and/or lepton numbers, which can be defined if there exist operators connecting the dark to the visible sector. As a result, the DM fields become intimately linked to the Standard Model (SM) ones and can be maximally asymmetric just like the ordinary matter. In particular, we discuss minimal scenarios where the DM is a complex scalar or a Dirac fermion coupled to operators with nonzero baryon and/or lepton numbers, and that consist of only SM fields. We consider an initial asymmetry stored in either the SM or the DM sector; the main role of these operators is to properly share the asymmetry between the two sectors, in accordance with observations. After the chemical decoupling, the DM and SM sectors do not care about each other as there is only an ineffective communication between them. Once the DM mass is specified, the Wilson coefficients of these operators are fixed by the requirement of the correct transfer of the asymmetry. We study the phenomenology of this framework at colliders, direct detection and indirect detection experiments. In particular, the LHC phenomenology is very rich and can be tested in different channels such as the two same-sign leptons with two jets, monojet and monojet with a monolepton.

  2. Sharing but not Caring: Dark Matter and the Baryon Asymmetry of the Universe

    CERN Document Server

    Bernal, Nicolás; Fonseca, Nayara

    2016-01-01

    We consider scenarios where Dark Matter (DM) particles carry baryon and/or lepton numbers, which can be defined if there exist operators connecting the dark to the visible sector. As a result, the DM fields become intimately linked to the Standard Model (SM) ones and can be maximally asymmetric just like the ordinary matter. In particular, we discuss minimal scenarios where the DM is a complex scalar or a Dirac fermion coupled to operators with nonzero baryon and/or lepton numbers, and that consist of only SM fields. We consider an initial asymmetry stored in either the SM or the DM sector; the main role of these operators is to properly $share$ the asymmetry between the two sectors, in accordance with observations. After the chemical decoupling, the DM and SM sectors do $not$ $care$ about each other as there is only an ineffective communication between them. Once the DM mass is specified, the Wilson coefficients of these operators are fixed by the requirement of the correct transfer of the asymmetry. We stud...

  3. Dark Matter

    CERN Document Server

    Einasto, Jaan

    2009-01-01

    A review of the development of the concept of dark matter is given. I begin the review with the description of the discovery of the mass paradox in our Galaxy and in clusters of galaxies. In mid 1970s the amount of observational data was sufficient to suggest the presence of a massive and invisible population around galaxies and in clusters of galaxies. The nature of the dark population was not clear at that time, but the hypotheses of stellar as well as of gaseous nature of the new population had serious difficulties. These difficulties disappeared when non-baryonic nature of dark matter was suggested in early 1980s. In addition to the presence of Dark Matter, recent observations suggest the presence of Dark Energy, which together with Dark Matter and ordinary baryonic matter makes the total matter/energy density of the Universe equal to the critical cosmological density. There are various hypothesis as for the nature of the dark matter particles, and generally some form of weakly interactive massive particl...

  4. Axino dark matter and baryon number asymmetry production by the Q-ball decay in gauge mediation

    Science.gov (United States)

    Kasuya, Shinta; Kawakami, Etsuko; Kawasaki, Masahiro

    2016-03-01

    We investigate the Q-ball decay into the axino dark matter in the gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays mainly into nucleons and partially into axinos to account respectively for the baryon asymmetry and the dark matter of the universe. The Q ball decays well before the big bang nucleosynthesis so that it is not affected by the decay. We show the region of the parameters which realizes this scenario.

  5. Influence of baryons on the orbital structure of dark matter haloes

    CERN Document Server

    Bryan, S E; Kay, S T; Schaye, J; Vecchia, C Dalla; Booth, C M

    2011-01-01

    We explore the dynamical signatures imprinted by baryons on dark matter haloes during the formation process using the OverWhelmingly Large Simulations (OWLS), a set of state-of-the-art high resolution cosmological hydrodynamical simulations. We present a detailed study of the effects of the implemented feedback prescriptions on the orbits of dark matter particles, stellar particles and subhaloes, analysing runs with no feedback, with stellar feedback and with feedback from supermassive black holes. We focus on the central regions (0.25 r_{200}) of haloes with virial masses ~ 6 x 10^{13} (~ 7 x 10^{11}) Msun/h at z = 0(2). We also investigate how the orbital content of these haloes depends on several key parameters such as their mass, redshift and dynamical state. The results of spectral analyses of the orbital content of these simulations are compared, and the change in fraction of box, tube and irregular orbits are quantified. Box orbits are found to dominate the orbital structure of dark matter haloes in co...

  6. Baryonic matter and beyond

    CERN Document Server

    Fukushima, Kenji

    2014-01-01

    We summarize recent developments in identifying the ground state of dense baryonic matter and beyond. The topics include deconfinement from baryonic matter to quark matter, a diquark mixture, topological effect coupled with chirality and density, and inhomogeneous chiral condensates.

  7. The evolving intergalactic medium - The uncollapsed baryon fraction in a cold dark matter universe

    Science.gov (United States)

    Shapiro, Paul R.; Giroux, Mark L.; Babul, Arif

    1991-01-01

    The time-varying density of the intergalactic medium (IGM) is calculated by coupling detailed numerical calculations of the thermal and ionization balance and radiative transfer in a uniform IGM of H and He to the linearized equations for the growth of density fluctuations in both gases and a dark component in a cold dark matter universe. The IGM density is identified with the collapsed baryon fraction. It is found that even if the IGM is never reheated, a significant fraction of the baryons remain uncollapsed at redshifts of four. If instead the collapsed fraction releases enough ionizing radiation or thermal energy to reionize the IGM by z greater than four as required by the Gunn-Peterson (GP) constraint, the uncollapsed fraction at z of four is even higher. The known quasar distribution is insufficient to supply the ionizing radiation necessary to satisfy the GP constraint in this case and, if stars are instead responsible, a substantial metallicity must have been produced by z of four.

  8. The connection between dark and baryonic matter in the process of galaxy formation

    Science.gov (United States)

    Trujillo, Sebastian

    Current galaxy formation theory still struggles to explain many essential galaxy properties. This thesis addresses these problems in the context of the interplay between baryons and dark matter in the concordance cosmological model. In the first part, we investigate galaxy abundance and scaling relations using a compilation of observational data along with large-scale cosmological simulations of dark matter (DM). We find that the standard cosmological model, in conjunction with halo abundance matching (HAM) and simple dynamical corrections, fits all basic statistics of galaxies more massive than the Large Magellanic Cloud (LMC). This zero-parameter model predicts the observed luminosity-velocity relation of early-and late-type galaxies, as well as the clustering of bright galaxies and the observed abundance of galaxies as a function of circular velocity. However, we find that all DM halos more massive than the LMC are much more abundant than the galaxies they host. Motivated by the model's shortcomings, in the second part we study the effect of baryons on galaxy formation using numerical simulations that include gas physics. We implement a model of star formation (SF) and stellar feedback based directly on observations of star-forming regions, where stellar feedback from massive stars includes radiation pressure, photoheating, supernovae, and stellar winds. We find that stellar radiation has a strong effect at z > 1, where it efficiently suppresses SF by dispersing cold and dense gas, preventing runaway growth of the stellar component, and yielding rising SF histories that reproduce many observations. Stellar feedback produces bulgeless discs with rotation curves and baryon fractions in excellent agreement with data. Feedback-driven blowouts reduce the central DM density of a dwarf, relieving tension between ACDM and observations. Based on these results, we begin to characterize the baryon cycle of galaxies and its imprint on studies of the circumgalactic medium

  9. Baryonic Distributions in Galaxy Dark Matter Haloes I: New Observations of Neutral and Ionized Gas Kinematics

    CERN Document Server

    Richards, Emily E; Barnes, K L; Staudaher, S; Dale, D A; Braun, T T; Wavle, D C; Dalcanton, J J; Bullock, J S; Chandar, R

    2016-01-01

    We present a combination of new and archival neutral hydrogen (HI) observations and new ionized gas spectroscopic observations for sixteen galaxies in the statistically representative EDGES kinematic sample. HI rotation curves are derived from new and archival radio synthesis observations from the Very Large Array (VLA) as well as processed data products from the Westerbork Radio Synthesis Telescope (WSRT). The HI rotation curves are supplemented with optical spectroscopic integral field unit (IFU) observations using SparsePak on the WIYN 3.5 m telescope to constrain the central ionized gas kinematics in twelve galaxies. The full rotation curves of each galaxy are decomposed into baryonic and dark matter halo components using 3.6$\\mu$m images from the Spitzer Space Telescope for the stellar content, the neutral hydrogen data for the atomic gas component, and, when available, CO data from the literature for the molecular gas component. Differences in the inferred distribution of mass are illustrated under fixe...

  10. Interacting photon-baryon fluid, warm dark matter, and the first acoustic peak

    Energy Technology Data Exchange (ETDEWEB)

    Fabris, Julio C.; Velasquez-Toribio, Alan M.; Zimdahl, Winfried [Universidade Federal do Espirito Santo, Departamento de Fisica, Vitoria, Espirito Santo (Brazil); Shapiro, Ilya L. [Universidade Federal de Juiz de Fora, Departamento de Fisica-ICE, Juiz de Fora, MG (Brazil); Tomsk State Pedagogical University, Tomsk (Russian Federation); Tomsk State University, Tomsk (Russian Federation)

    2014-07-15

    The Reduced Relativistic Gas (RRG) model was introduced by A. Sakharov in 1965 for deriving the cosmic microwave background (CMB) spectrum. It was recently reinvented by some of us to achieve an interpolation between the radiation and dust epochs in the evolution of the Universe. This model circumvents the complicated structure of the Boltzmann-Einstein system of equations and admits a transparent description of warm-dark-matter effects. It is extended here to include, on a phenomenological basis, an out-of-equilibrium interaction between radiation and baryons which is supposed to account for relevant aspects of pre-recombination physics in a simplified manner. Furthermore, we use the tight-coupling approximation to explore the influence of both this interaction and of the RRG warmness parameter on the anisotropy spectrum of the CMB. The predictions of the model are very similar to those of the ΛCDM model if both the interaction and the dark-matter warmness parameters are of the order of 10{sup -4} or smaller. As far as the warmness parameter is concerned, this is in good agreement with previous estimations on the basis of results from structure formation. (orig.)

  11. Interacting photon-baryon fluid, warm dark matter and the first acoustic peak

    CERN Document Server

    Fabris, Julio C; Zimdahl, Winfried; Shapiro, Ilya L

    2013-01-01

    The Reduced Relativistic Gas (RRG) model was introduced by A. Sakharov in 1965 for deriving the cosmic microwave background (CMB) spectrum. It was recently reinvented by some of us to achieve an interpolation between the radiation and dust epochs in the evolution of the Universe. This model circumvents the complicated structure of the Boltzmann-Einstein system of equations and admits a transparent description of warm-dark-matter effects. It is extended here to include, on a phenomenological basis, an out-of-equilibrium interaction between radiation and baryons which is supposed to account for relevant aspects of pre-recombination physics in a simplified manner. Furthermore, we use the tight-coupling approximation to explore the influence of both this interaction and of the RRG warmness parameter on the anisotropy spectrum of the CMB. The predictions of the model are very similar to those of the {\\Lambda}CDM model if both the interaction and the dark-matter warmness parameters are of the order of $10^{-4}$ or ...

  12. TASI Lectures on Dark Matter

    OpenAIRE

    Olive, Keith A.

    2003-01-01

    Observational evidence and theoretical motivation for dark matter are presented and connections to the CMB and BBN are made. Problems for baryonic and neutrino dark matter are summarized. Emphasis is placed on the prospects for supersymmetric dark matter.

  13. Dark Matter

    OpenAIRE

    Zacek, Viktor

    2007-01-01

    The nature of the main constituents of the mass of the universe is one of the outstanding riddles of cosmology and astro-particle physics. Current models explaining the evolution of the universe, and measurements of the various components of its mass, all have in common that an appreciable contribution to that mass is non-luminous and non-baryonic, and that a large fraction of this so-called dark matter must be in the form of non-relativistic massive particles (Cold Dark Matter: CDM). In the ...

  14. Astrophysical constraints on dark-matter Q-balls in the presence of baryon-violating operators

    CERN Document Server

    Cotner, Eric

    2016-01-01

    Supersymmetric extensions of the standard model predict the existence of non-topological solitons, Q-balls. Assuming the standard cosmological history preceded by inflation, Q-balls can form in the early universe and can make up the dark matter. The relatively large masses of such dark-matter particles imply a low number density, making direct detection very challenging. The strongest limits come from the existence of neutron stars because, if a baryonic Q-ball is captured by a neutron star, the Q-ball can absorb the baryon number releasing energy and eventually destroying a neutron star. However, in the presence of baryon number violating higher-dimension operators, the growth of a Q-ball inside a neutron star is hampered once the Q-ball reaches a certain size. We re-examine the limits and identify some classes of higher-dimensional operators for which supersymmetric Q-balls can account for dark matter. The present limits leave a wide range of parameters available for dark matter in the form of supersymmetri...

  15. Tully-Fisher relation, key to dark matter companion of baryonic matter

    CERN Document Server

    Sobouti, Y; Haghi, H

    2009-01-01

    Rotation curves of spiral galaxies \\emph{i}) fall off much less steeply than the Keplerian curves do, and \\emph{ii}) have far-distance asymptotic speeds (almost) proportional to the fourth root of the mass of the galaxy, the Tully-Fisher relation. These features alone are sufficient to assign a dark companion to the galaxy in an unambiguous way. In regions exterior to a spherical system, we design a spherically symmetric spacetime to accommodate the idiosyncracy just quoted. In the weak field regime, an excess gravitation over what the observable matter can produce, emerges. We attribute it to a hypothetical dark perfect fluid companion to the galaxy, and resort to the Tully-Fisher relation to deduce its density and pressure. The dark density turns out to be proportional to the square root of the mass of the galaxy, and to fall off as $r^{-(2+\\alpha)}, ~\\alpha\\ll 1$. The dark equation of state is barrotropic. For the interior of the configuration, we require the continuity of the total force field at the boun...

  16. Particle Dark Matter

    OpenAIRE

    Drees, Manuel

    1996-01-01

    Several lines of evidence suggest that some of the dark matter may be non-baryonic: the non-detection of various plausible baryonic candidates for dark matter inferred, e.g., from galaxy rotation curves and from cluster of galaxy velocity dispersions, the need for non-baryonic dark matter for theoretical models of galaxy formation, and the large discrepancy between dynamical measurements implying $\\Omega_0 > 0.2$ and the baryon abundance inferred from big bang nucleosynthesis, $\\Omega_b h^2 =...

  17. Neutrino mass, dark matter, and Baryon asymmetry via TeV-scale physics without fine-tuning.

    Science.gov (United States)

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2009-02-01

    We propose an extended version of the standard model, in which neutrino oscillation, dark matter, and the baryon asymmetry of the Universe can be simultaneously explained by the TeV-scale physics without assuming a large hierarchy among the mass scales. Tiny neutrino masses are generated at the three-loop level due to the exact Z2 symmetry, by which the stability of the dark matter candidate is guaranteed. The extra Higgs doublet is required not only for the tiny neutrino masses but also for successful electroweak baryogenesis. The model provides discriminative predictions especially in Higgs phenomenology, so that it is testable at current and future collider experiments. PMID:19257506

  18. Neutrino mass, Dark Matter and Baryon Asymmetry via TeV-Scale Physics without Fine-Tuning

    OpenAIRE

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2008-01-01

    We propose an extended version of the standard model, in which neutrino oscillation, dark matter, and baryon asymmetry of the Universe can be simultaneously explained by the TeV-scale physics without assuming unnatural hierarchy among the mass scales. Tiny neutrino masses are generated at the three loop level due to the exact $Z_2$ symmetry, by which stability of the dark matter candidate is guaranteed. The extra Higgs doublet is required not only for the tiny neutrino masses but also for suc...

  19. ILC phenomenology in a TeV scale radiative seesaw model for neutrino mass, dark matter and baryon asymmetry

    OpenAIRE

    Aoki, Mayumi; Kanemura, Shinya; Seto, Osamu

    2010-01-01

    We discuss phenomenology in a new TeV scale model which would explain neutrino oscillation, dark matter, and baryon asymmetry of the Universe simultaneously by the dynamics of the extended Higgs sector and TeV-scale right-handed neutrinos. Tiny neutrino masses are generated at the three-loop level due to the exact $Z_2$ symmetry, by which the stability of the dark matter candidate is guaranteed. The model provides various discriminative predictions in Higgs phenomenology, which can be tested ...

  20. Dark Matter

    CERN Document Server

    Zacek, Viktor

    2007-01-01

    The nature of the main constituents of the mass of the universe is one of the outstanding riddles of cosmology and astro-particle physics. Current models explaining the evolution of the universe, and measurements of the various components of its mass, all have in common that an appreciable contribution to that mass is non-luminous and non-baryonic, and that a large fraction of this so-called dark matter must be in the form of non-relativistic massive particles (Cold Dark Matter: CDM). In the spirit of the Lake Louise Winter Institute Lectures we take a look at the latest astronomical discoveries and report on the status of direct and indirect Dark Matter searches.

  1. Effects of baryons on the dark matter distribution in cosmological hydrodynamical simulations

    OpenAIRE

    Schaller, Matthieu; Frenk, Carlos S.; Bower, Richard G.

    2015-01-01

    Simulations including solely dark matter performed over the last three decades have delivered an accurate and robust description of the cosmic web and dark matter structures. With the advent of more precise cosmological probes, planned and ongoing, and dark matter detection experiments, this numerical modelling has to be improved to incorporate the complex non-linear and energetic processes taking place during galaxy formation. We use the ``Evolution and Assembly of GaLaxies and their Environ...

  2. Dark Matter: Early Considerations

    OpenAIRE

    Einasto, J.

    2004-01-01

    A review of the study of dark matter is given, starting with earliest studies and finishing with the establishment of the standard Cold Dark Matter paradigm in mid 1980-s. Particular attention is given to the collision of the classical and new paradigms concerning the matter content of the Universe. Also the amount of baryonic matter, dark matter and dark energy is discussed using modern estimates.

  3. Disentangling Baryons and Dark Matter in the Spiral Gravitational Lens B1933+503

    CERN Document Server

    Suyu, S H; McKean, J P; Fassnacht, C D; Treu, T; Halkola, A; Norbury, M; Jackson, N; Schneider, P; Thompson, D; Auger, M W; Koopmans, L V E; Matthews, K

    2011-01-01

    Measuring the relative mass contributions of luminous and dark matter in spiral galaxies is important for understanding their formation and evolution. The combination of a galaxy rotation curve and strong lensing is a powerful way to break the disk-halo degeneracy that is inherent in each of the methods individually. We present an analysis of the 10-image radio spiral lens B1933+503 at z_l=0.755, incorporating (1) new global VLBI observations, (2) new adaptive-optics assisted K-band imaging, (3) new spectroscopic observations for the lens galaxy rotation curve and the source redshift. We construct a three-dimensionally axisymmetric mass distribution with 3 components: an exponential profile for the disk, a point mass for the bulge, and an NFW profile for the halo. The mass model is simultaneously fitted to the kinematics and the lensing data. The NFW halo needs to be oblate with a flattening of a/c=0.33^{+0.07}_{-0.05} to be consistent with the radio data. This suggests that baryons are effective at making th...

  4. Baryonic distributions in galaxy dark matter haloes - I. New observations of neutral and ionized gas kinematics

    Science.gov (United States)

    Richards, Emily E.; van Zee, L.; Barnes, K. L.; Staudaher, S.; Dale, D. A.; Braun, T. T.; Wavle, D. C.; Dalcanton, J. J.; Bullock, J. S.; Chandar, R.

    2016-07-01

    We present a combination of new and archival neutral hydrogen (H I) observations and new ionized gas spectroscopic observations for 16 galaxies in the statistically representative Extended Disk Galaxy Explore Science kinematic sample. H I rotation curves are derived from new and archival radio synthesis observations from the Very Large Array (VLA) as well as processed data products from the Westerbork Radio Synthesis Telescope (WSRT). The H I rotation curves are supplemented with optical spectroscopic integral field unit (IFU) observations using SparsePak on the WIYN 3.5 m telescope to constrain the central ionized gas kinematics in 12 galaxies. The full rotation curves of each galaxy are decomposed into baryonic and dark matter halo components using 3.6μm images from the Spitzer Space Telescope for the stellar content, the neutral hydrogen data for the atomic gas component, and, when available, CO data from the literature for the molecular gas component. Differences in the inferred distribution of mass are illustrated under fixed stellar mass-to-light ratio (M/L) and maximum disc/bulge assumptions in the rotation curve decomposition.

  5. Structure of Dark Matter and Baryons in AMIBA SZE Galaxy Clusters (II)

    Science.gov (United States)

    Ho, Paul

    2010-01-01

    We propose deep BR_cz' imaging with Suprime-Cam of several hot X-ray (> 8 keV) clusters of galaxies for which Sunyaev-Zel'dovich effect (SZE) observations are underway at 3mm with the Array for Microwave Background Anisotropy (AMiBA) and superb resolution HST/ACS strong lensing (SL) data are readily available. Joint weak lensing (WL), SL, multicolor imaging, and SZE observations, combined with archival X-ray data, will probe in a model-independent manner the structure of dark matter, member galaxies, and the hot cluster gas in rich cluster environments. Our targets are composed of a class of the most massive clusters at moderate redshifts (0.2 <~ z <~ 0.7), allowing us to derive reliable WL shape measurements and thus accurate mass profiles out to the cluster virial radius. Our proposal aims to (1) map out the mass distribution in clusters via WL techniques, and compare with the distributions of hot and cold baryonic components, (2) make an accurate determination of the cluster mass profile from a joint WL+SL analysis, (3) derive cluster gas-mass fraction profiles free from the hydrostatic equilibrium assumption, and (4) examine directly the cluster mass vs. SZE observable relation, which will provide an important basis for cosmological tests with upcoming blind SZE surveys.

  6. Dark matter and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N.

    1992-03-01

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between cold'' and hot'' non-baryonic candidates is shown to depend on the assumed seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  7. Dark matter and cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N.

    1992-03-01

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the {Omega} = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ``cold`` and ``hot`` non-baryonic candidates is shown to depend on the assumed ``seeds`` that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed.

  8. Dark matter and cosmology

    International Nuclear Information System (INIS)

    The cosmological dark matter problem is reviewed. The Big Bang Nucleosynthesis constraints on the baryon density are compared with the densities implied by visible matter, dark halos, dynamics of clusters, gravitational lenses, large-scale velocity flows, and the Ω = 1 flatness/inflation argument. It is shown that (1) the majority of baryons are dark; and (2) non-baryonic dark matter is probably required on large scales. It is also noted that halo dark matter could be either baryonic or non-baryonic. Descrimination between ''cold'' and ''hot'' non-baryonic candidates is shown to depend on the assumed ''seeds'' that stimulate structure formation. Gaussian density fluctuations, such as those induced by quantum fluctuations, favor cold dark matter, whereas topological defects such as strings, textures or domain walls may work equally or better with hot dark matter. A possible connection between cold dark matter, globular cluster ages and the Hubble constant is mentioned. Recent large-scale structure measurements, coupled with microwave anisotropy limits, are shown to raise some questions for the previously favored density fluctuation picture. Accelerator and underground limits on dark matter candidates are also reviewed

  9. Dense Baryonic Matter

    International Nuclear Information System (INIS)

    Experiments on strangeness production in nucleus-nucleus collisions at SIS energies address fundamental aspects of modern nuclear physics: the determination of the nuclear equation-of-state at high baryon densities and the properties of hadrons in dense nuclear matter. Experimental data and theoretical results will be reviewed. Future experiments at the FAIR accelerator aim at the exploration of the QCD phase diagram at highest baryon densities. The proposal for the Compressed Baryonic Matter (CBM) experiment will be presented. (author)

  10. Disentangling Baryons and Dark Matter in the Spiral Gravitational Lens B1933+503

    Science.gov (United States)

    Suyu, S. H.; Hensel, S. W.; McKean, J. P.; Fassnacht, C. D.; Treu, T.; Halkola, A.; Norbury, M.; Jackson, N.; Schneider, P.; Thompson, D.; Auger, M. W.; Koopmans, L. V. E.; Matthews, K.

    2012-05-01

    Measuring the relative mass contributions of luminous and dark matter in spiral galaxies is important for understanding their formation and evolution. The combination of a galaxy rotation curve and strong lensing is a powerful way to break the disk-halo degeneracy that is inherent in each of the methods individually. We present an analysis of the 10 image radio spiral lens B1933+503 at z l = 0.755, incorporating (1) new global very long baseline interferometry observations, (2) new adaptive-optics-assisted K-band imaging, and (3) new spectroscopic observations for the lens galaxy rotation curve and the source redshift. We construct a three-dimensionally axisymmetric mass distribution with three components: an exponential profile for the disk, a point mass for the bulge, and a Navarro-Frenk-White (NFW) profile for the halo. The mass model is simultaneously fitted to the kinematics and the lensing data. The NFW halo needs to be oblate with a flattening of a/c = 0.33+0.07 -0.05 to be consistent with the radio data. This suggests that baryons are effective at making the halos oblate near the center. The lensing and kinematics analysis probe the inner ~10 kpc of the galaxy, and we obtain a lower limit on the halo scale radius of 16 kpc (95% credible intervals). The dark matter mass fraction inside a sphere with a radius of 2.2 disk scale lengths is f DM, 2.2 = 0.43+0.10 -0.09. The contribution of the disk to the total circular velocity at 2.2 disk scale lengths is 0.76+0.05 -0.06, suggesting that the disk is marginally submaximal. The stellar mass of the disk from our modeling is log10(M */M ⊙) = 11.06+0.09 -0.11 assuming that the cold gas contributes ~20% to the total disk mass. In comparison to the stellar masses estimated from stellar population synthesis models, the stellar initial mass function of Chabrier is preferred to that of Salpeter by a probability factor of 7.2.

  11. Detectors calibration and research of luminescent materials for non baryonic dark matter detection

    International Nuclear Information System (INIS)

    This work is dedicated to the characterization of luminescent materials in order to build bolometers for the simultaneous detection of heat an light in the search for WIMPs (Weakly Interacting Massive Particles) candidates for non baryonic dark matter. These double bolometers should enable the identification and measurement of recoil ions after collision between a WIMPs and material nucleus. In our search for highly luminescent materials, we have studied the emission spectra, the time response and the spectra response resulting from laser excitation or ionizing particles bombardment of some crystals such as CaF2(Eu), CaF2, CeF3(Ce) and In2Si2O7. These studies were conducted down to liquid Helium temperature (4 K). After showing the good performance of CaF2(Eu) scintillator, we have measured the quenching effect resulting from 19F and Ca ions recoil in CaF2(Eu). This was done at the 14 MeV Tandem accelerator of Bruyeres-Le-Chatel with a pulsed neutron beam, simulating the WIMPs. The data obtained allowed the exploitation of the results of the BPRS (Beijing - Rome - Paris - Saclay) experiments carried out at Gran-Sasso. This results showed a gain of up to an order of magnitude in the exclusion graph of axially coupled WIMPs compared to NaI. With the apparatus developed at IPN Lyon (Nuclear Physical Institute of Lyon), we have also measured the ionization induced by Ge ion recoils in Germanium detector, which is one of the most promising crystals for WIMPs detection in the energy range of 2.8 keV-37.8 keV. An ionization efficiency of 24% to 29% was obtained. (author). refs., figs., tabs

  12. Cosmological perturbation theory for baryons and dark matter I. One-loop corrections in the RPT framework

    Energy Technology Data Exchange (ETDEWEB)

    Somogyi, Gabor [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Zurich Univ. (Switzerland). Inst. for Theoretical Physics; Smith, Robert E. [Zurich Univ. (Switzerland). Inst. for Theoretical Physics

    2009-10-15

    We generalize the ''renormalized'' perturbation theory (RPT) formalism of M. Crocce and R. Scoccimarro (2006) to deal with multiple fluids in the Universe and here we present the complete calculations up to the one-loop level in the RPT. We apply this approach to the problem of following the nonlinear evolution of baryon and cold dark matter (CDM) perturbations, evolving from the distinct sets of initial conditions, from the high redshift post-recombination Universe right through to the present day. In current theoretical and numerical models of structure formation, it is standard practice to treat baryons and CDM as an effective single matter fluid - the so called dark matter only modeling. In this approximation, one uses a weighed sum of late time baryon and CDM transfer functions to set initial mass fluctuations. In this paper we explore whether this approach can be employed for high precision modeling of structure formation. We show that, even if we only follow the linear evolution, there is a large-scale scale-dependent bias between baryons and CDM for the currently favored WMAP5 {lambda}CDM model. This time evolving bias is significant (> 1%) until the present day, when it is driven towards unity through gravitational relaxation processes. Using the RPT formalism we test this approximation in the non-linear regime. We show that the non-linear CDM power spectrum in the 2-component fluid differs from that obtained from an effective mean-mass 1-component fluid by {proportional_to} 3% on scales of order k {proportional_to} 0.05 h Mpc{sup -1} at z = 10, and by {proportional_to} 0.5% at z = 0. However, for the case of the non-linear evolution of the baryons the situation is worse and we find that the power spectrum is suppressed, relative to the total matter, by {proportional_to} 15% on scales k {proportional_to} 0.05 hMpc{sup -1} at z = 10, and by {proportional_to} 3 - 5% at z = 0. Importantly, besides the suppression of the spectrum, the

  13. The impact of the supersonic baryon-dark matter velocity difference on the z~20 21cm background

    CERN Document Server

    McQuinn, Matthew

    2012-01-01

    Recently, Tseliakhovich and Hirata (2010) showed that during the cosmic Dark Ages the baryons were typically moving supersonically with respect to the dark matter with a spatially variable Mach number. Such supersonic motion may source shocks that heat the Universe. This motion may also suppress star formation in the first halos. Even a small amount of coupling of the 21cm signal to this motion has the potential to vastly enhance the 21cm brightness temperature fluctuations at 15dark matter-baryon relative velocity, v_bc (in contrast to prior simulations). We find that the supersonic velocity difference dramatically suppresses structure formation at 10-100 comoving kpc scales, it sources shocks throug...

  14. The variation of rotation curve shapes as a signature of the effects of baryons on dark matter density profiles

    Science.gov (United States)

    Brook, Chris B.

    2015-12-01

    Rotation curves of galaxies show a wide range of shapes, which can be paramaterized as scatter in Vrot(1 kpc)/Vmax , i.e. the ratio of the rotation velocity measured at 1 kpc and the maximum measured rotation velocity. We examine whether the observed scatter can be accounted for by combining scatters in disc scalelengths, the concentration-halo mass relation, and the M⋆-Mhalo relation. We use these scatters to create model galaxy populations; when housed within dark matter haloes that have universal, Navarro, Frenk & White density profiles, the model does not match the lowest observed values of Vrot(1 kpc)/Vmax and has too little scatter in Vrot(1 kpc)/Vmax compared to observations. By contrast, a model using a mass-dependent dark matter profile, where the inner slope is determined by the ratio of M⋆/Mhalo, produces galaxies with low values of Vrot(1 kpc)/Vmax and a much larger scatter, both in agreement with observation. We conclude that the large observed scatter in Vrot(1 kpc)/Vmax favours density profiles that are significantly affected by baryonic processes. Alternative dark matter core formation models such as self-interacting dark matter may also account for the observed variation in rotation curve shapes, but these observations may provide important constraints in terms of core sizes, and whether they vary with halo mass and/or merger history.

  15. Baryons do trace dark matter 380,000 years after the big bang: Search for compensated isocurvature perturbations with WMAP 9-year data

    CERN Document Server

    Grin, Daniel; Holder, Gilbert; Doré, Olivier; Kamionkowski, Marc

    2014-01-01

    Primordial isocurvature fluctuations between photons and either neutrinos or non-relativistic species such as baryons or dark matter are known to be sub-dominant to adiabatic fluctuations. Perturbations in the relative densities of baryons and dark matter (known as compensated isocurvature perturbations, or CIPs), however, are surprisingly poorly constrained. CIPs leave no imprint in the cosmic microwave background (CMB) on observable scales, at least at linear order in their amplitude and zeroth order in the amplitude of adiabatic perturbations. It is thus not yet empirically known if baryons trace dark matter at the surface of last scattering. If CIPs exist, they would spatially modulate the Silk damping scale and acoustic horizon, causing distinct fluctuations in the CMB temperature/polarization power spectra across the sky: this effect is first order in both the CIP and adiabatic mode amplitudes. Here, temperature data from the Wilkinson Microwave Anisotropy Probe (WMAP) are used to conduct the first CMB-...

  16. Dark group: dark energy and dark matter

    International Nuclear Information System (INIS)

    We study the possibility that a dark group, a gauge group with particles interacting with the standard model particles only via gravity, is responsible for containing the dark energy and dark matter required by present day observations. We show that it is indeed possible and we determine the constrains for the dark group. The non-perturbative effects generated by a strong gauge coupling constant can de determined and a inverse power law scalar potential IPL for the dark meson fields is generated parameterizing the dark energy. On the other hand it is the massive particles, e.g., dark baryons, of the dark gauge group that give the corresponding dark matter. The mass of the dark particles is of the order of the condensation scale Λc and the temperature is smaller then the photon's temperature. The dark matter is of the warm matter type. The only parameters of the model are the number of particles of the dark group. The allowed values of the different parameters are severely restricted. The dark group energy density at Λc must be ΩDGc≤0.17 and the evolution and acceptable values of dark matter and dark energy leads to a constrain of Λc and the IPL parameter n giving Λc=O(1-103) eV and 0.28≤n≤1.04

  17. Dark Matter Superfluidity

    OpenAIRE

    Khoury, Justin

    2016-01-01

    In this talk I summarize a novel framework that unifies the stunning success of MOND on galactic scales with the triumph of the $\\Lambda$CDM model on cosmological scales. This is achieved through the rich and well-studied physics of superfluidity. The dark matter and MOND components have a common origin, representing different phases of a single underlying substance. In galaxies, dark matter thermalizes and condenses to form a superfluid phase. The superfluid phonons couple to baryonic matter...

  18. Dark galactic halos without dark matter

    OpenAIRE

    Nesbet, R. K.

    2011-01-01

    Using standard Einstein theory, baryonic mass cannot account for observed galactic rotation velocities and gravitational lensing, attributed to galactic dark matter halos. In contrast, theory constrained by Weyl conformal scaling symmetry explains observed galactic rotation in the halo region without invoking dark matter. An explanation of dark halos, gravitational lensing, and structural stabilization, without dark matter and consistent with conformal theory, is proposed here. Condensation o...

  19. Quirky composite dark matter

    Science.gov (United States)

    Kribs, Graham D.; Roy, Tuhin S.; Terning, John; Zurek, Kathryn M.

    2010-05-01

    We propose a new dark matter candidate, “quirky dark matter,” that is a scalar baryonic bound state of a new non-Abelian force that becomes strong below the electroweak scale. The bound state is made of chiral quirks: new fermions that transform under both the new strong force as well as in a chiral representation of the electroweak group, acquiring mass from the Higgs mechanism. Electric charge neutrality of the lightest baryon requires approximately degenerate quirk masses which also causes the charge radius of the bound state to be negligible. The abundance is determined by an asymmetry that is linked to the baryon and lepton numbers of the universe through electroweak sphalerons. Dark matter elastic scattering with nuclei proceeds through Higgs exchange as well as an electromagnetic polarizability operator which is just now being tested in direct detection experiments. A novel method to search for quirky dark matter is to look for a gamma-ray “dark line” spectroscopic feature in galaxy clusters that result from the quirky Lyman-alpha or quirky hyperfine transitions. Colliders are expected to dominantly produce quirky mesons, not quirky baryons, consequently large missing energy is not the primary collider signal of the physics associated with quirky dark matter.

  20. Quirky composite dark matter

    International Nuclear Information System (INIS)

    We propose a new dark matter candidate, 'quirky dark matter', that is a scalar baryonic bound state of a new non-Abelian force that becomes strong below the electroweak scale. The bound state is made of chiral quirks: new fermions that transform under both the new strong force as well as in a chiral representation of the electroweak group, acquiring mass from the Higgs mechanism. Electric charge neutrality of the lightest baryon requires approximately degenerate quirk masses which also causes the charge radius of the bound state to be negligible. The abundance is determined by an asymmetry that is linked to the baryon and lepton numbers of the universe through electroweak sphalerons. Dark matter elastic scattering with nuclei proceeds through Higgs exchange as well as an electromagnetic polarizability operator which is just now being tested in direct detection experiments. A novel method to search for quirky dark matter is to look for a gamma-ray 'dark line' spectroscopic feature in galaxy clusters that result from the quirky Lyman-alpha or quirky hyperfine transitions. Colliders are expected to dominantly produce quirky mesons, not quirky baryons, consequently large missing energy is not the primary collider signal of the physics associated with quirky dark matter.

  1. The Entire Virial Radius of the Fossil Cluster RXJ1159+5531: II. Dark Matter and Baryon Fraction

    CERN Document Server

    Buote, David A; Gastaldello, Fabio; Brighenti, Fabrizio

    2016-01-01

    In this second paper on the entire virial region of the relaxed fossil cluster RXJ1159+5531, we present a hydrostatic analysis of the hot intracluster medium (ICM). For a model consisting of ICM, stellar mass from the central galaxy (BCG), and an NFW dark matter (DM) halo, we obtain good descriptions of the projected radial profiles of ICM emissivity and temperature. The BCG stellar mass is clearly detected with M_star/L_K = 0.61 +/- 0.11 solar, consistent with stellar population synthesis models for a Milky-Way IMF. We obtain a halo concentration, c_200 =8.4 +/- 1.0, and virial mass, M_200 = 7.9 +/- 0.6 x 10^13 M_sun. For its mass, the inferred concentration is larger than most relaxed halos produced in cosmological simulations with Planck parameters, consistent with RXJ1159+5531 forming earlier than the general halo population. The baryon fraction at r_200, f_b,200 = 0.134 +/- 0.007, is slightly below the Planck value (0.155) for the universe. When we account for the stellar baryons associated with non-cent...

  2. Asymmetric twin Dark Matter

    International Nuclear Information System (INIS)

    We study a natural implementation of Asymmetric Dark Matter in Twin Higgs models. The mirroring of the Standard Model strong sector suggests that a twin baryon with mass around 5 GeV is a natural Dark Matter candidate once a twin baryon number asymmetry comparable to the SM asymmetry is generated. We explore twin baryon Dark Matter in two different scenarios, one with minimal content in the twin sector and one with a complete copy of the SM, including a light twin photon. The essential requirements for successful thermal history are presented, and in doing so we address some of the cosmological issues common to many Twin Higgs models. The required interactions we introduce predict signatures at direct detection experiments and at the LHC

  3. THE IMPACT OF THE SUPERSONIC BARYON-DARK MATTER VELOCITY DIFFERENCE ON THE z {approx} 20 21 cm BACKGROUND

    Energy Technology Data Exchange (ETDEWEB)

    McQuinn, Matthew; O' Leary, Ryan M. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States)

    2012-11-20

    Recently, Tseliakhovich and Hirata showed that during the cosmic Dark Ages the baryons were typically moving supersonically with respect to the dark matter with a spatially variable Mach number. Such supersonic motion may source shocks that inhomogeneously heat the universe. This motion may also suppress star formation in the first halos. Even a small amount of coupling of the 21 cm signal to this motion has the potential to vastly enhance the 21 cm brightness temperature fluctuations at 15 {approx}< z {approx}< 40, as well as to imprint distinctive acoustic oscillations in this signal. We present estimates for the size of this coupling, which we calibrate with a suite of cosmological simulations of the high-redshift universe using the GADGET and Enzo codes. Our simulations, discussed in detail in a companion paper, are initialized to self-consistently account for gas pressure and the dark matter-baryon relative velocity, v {sub bc} (in contrast to prior simulations). We find that the supersonic velocity difference dramatically suppresses structure formation on 10-100 comoving kpc scales, it sources shocks throughout the universe, and it impacts the accretion of gas onto the first star-forming minihalos (even for halo masses as large as 10{sup 7} M {sub Sun }). However, prior to reheating by astrophysical sources, we find that the v {sub bc}-sourced temperature fluctuations can contribute only as much as Almost-Equal-To 10% of the fluctuations in the 21 cm signal. We do find that v {sub bc} in certain scenarios could source an O(1) component in the power spectrum of the 21 cm background on observable scales via the X-ray (but not ultraviolet) backgrounds produced once the first stars formed. In a scenario in which {approx}10{sup 6} M {sub Sun} minihalos reheated the universe via their X-ray backgrounds, we find that the pre-reionization 21 cm signal would be larger than previously anticipated and exhibit more significant acoustic features. Such features would be a

  4. Dark Matter with Variable Masses

    OpenAIRE

    Garcia-Bellido, Juan

    1992-01-01

    String effective theories contain a dilaton scalar field which couples to gravity, matter and radiation. In general, particle masses will have different dilaton couplings. We can always choose a conformal frame in which baryons have constant masses while (non--baryonic) dark matter have variable masses, in the context of a scalar--tensor gravity theory. We are interested in the phenomenology of this scenario. Dark matter with variable masses could have a measurable effect on the dynamical mot...

  5. Dissecting Galaxy Formation: I. Comparison Between Pure Dark Matter and Baryonic Models

    CERN Document Server

    Romano-Diaz, Emilio; Heller, Clayton; Hoffman, Yehuda

    2009-01-01

    We compare assembly of DM halos with and without baryons, within the context of cosmological evolution in the LCDM WMAP3 Universe (baryons+DM, BDM model, and pure DM, PDM model). In representative PDM and BDM models we find that baryons contribute decisively to the evolution of the central region, leading to an isothermal DM cusp, and to a flat DM density core -- the result of heating by dynamical friction of the substructure during a quiescent evolution epoch. This process ablates the cold gas from an embedded disk, cutting the star formation rate by ~10, and heats up the spheroidal gas and stellar components, triggering their expansion. The substructure is more resilient in the presence of baryons. The disk which formed from inside-out as gas dominated, is transformed into an intermediate Hubble type by z ~ 2 and to an early type by z ~ 0.5, based on its gas contents and spheroidal-to-disk stellar mass ratio. Only a relatively small ~20% fraction of DM particles in PDM and BDM models are bound within the ra...

  6. Constraining the Baryon-Dark Matter Relative Velocity with the Large-Scale 3-Point Correlation Function of the SDSS BOSS DR12 CMASS Galaxies

    OpenAIRE

    Slepian, Zachary; Eisenstein, Daniel J.; Blazek, Jonathan A.; Brownstein, Joel R.; Chuang, Chia-Hsun; Gil-Marín, Héctor; Ho, Shirley; Kitaura, Francisco-Shu; McEwen, Joseph E.; Percival, Will J.; Ross, Ashley J.; Rossi, Graziano; Seo, Hee-Jong; Slosar, Anže; Vargas-Magaña, Mariana

    2016-01-01

    We search for a galaxy clustering bias due to a modulation of galaxy number with the baryon-dark matter relative velocity resulting from recombination-era physics. We find no detected signal and place the constraint $b_v < 0.01$ on the relative velocity bias for the CMASS galaxies. This bias is an important potential systematic of Baryon Acoustic Oscillation (BAO) method measurements of the cosmic distance scale using the 2-point clustering. Our limit on the relative velocity bias indicates a...

  7. Black Holes as Dark Matter

    OpenAIRE

    Frampton, Paul H.

    2009-01-01

    While the energy of the universe has been established to be about 0.04 baryons, 0.24 dark matter and 0.72 dark energy, the cosmological entropy is almost entirely, about $(1 - 10^{-15})$, from black holes and only $10^{-15}$ from everything else. This identification of all dark matter as black holes is natural in statistical mechanics. Cosmological history of dark matter is discussed.

  8. A search for non-baryonic dark matter using an ionisation bolometer in the edelweiss experiment

    International Nuclear Information System (INIS)

    The EDELWEISS experiment is an underground direct-detection search for hypothetical supersymmetric WIMPs that might solve the problem of dark matter. We have employed a cryogenic 70 g germanium ionisation bolometer, in which a WIMP would scatter elastically off a nucleus, creating both a heat and an ionisation signal. To offset the various electronic noises present in our necessarily small signals, we have s applied an optimal filtering technique in the frequency domain. This allows us to reach resolutions of 1.2 keV FWHM at 122 keV on north channels. It also provides good separation right down to low energies between the expected signal of nuclear recoils, and the photonic background of electron recoils which ionize more for a given energy. Calibration data show that we are able to reject 99.7 % of this background, while keeping 95% of the signal. However, our 1.17 kg.days of data searching for WIMPs show a third population encroaching on the expected signal. This is probably due to low energy photons or electrons interacting in the outer layers of the crystal, where charges are incompletely collected. Nevertheless, by trading off half of the conserved signal, we still manage to reject 98.5 % of the background. Thus the raw rate of 40 evts/d/kg/keV yields a conservative 90 % upper limit on the signal of 0.6 evts/d/kg/keV. This represents nearly a three orders of magnitude improvement for EDELWEISS, and puts the predicted supersymmetric phase space within two orders of magnitude. (author)

  9. The Entire Virial Radius of the Fossil Cluster RXJ 1159 + 5531. II. Dark Matter and Baryon Fraction

    Science.gov (United States)

    Buote, David A.; Su, Yuanyuan; Gastaldello, Fabio; Brighenti, Fabrizio

    2016-08-01

    In this second paper on the entire virial region of the relaxed fossil cluster RXJ 1159+5531, we present a hydrostatic analysis of the azimuthally averaged hot intracluster medium (ICM) using the results of Su et al. For a model consisting of ICM, stellar mass from the central galaxy (BCG), and an NFW dark matter (DM) halo, we obtain a good description of the projected radial profiles of ICM emissivity and temperature that yield precise constraints on the total mass profile. The BCG stellar mass component is clearly detected with a K-band stellar mass-to-light ratio, {M}\\star /{L}K=0.61+/- 0.11 {M}ȯ /{L}ȯ , consistent with stellar population synthesis models for a Milky Way initial mass function. We obtain a halo concentration, {c}200=8.4+/- 1.0, and virial mass, {M}200=(7.9+/- 0.6)× {10}13 {M}ȯ . For its mass, the inferred concentration is larger than most relaxed halos produced in cosmological simulations with Planck parameters, consistent with RXJ 1159+5531 forming earlier than the general halo population. The baryon fraction at r 200, {f}{{b,200}}=0.134+/- 0.007, is slightly below the Planck value (0.155) for the universe. However, when we take into account the additional stellar baryons associated with non-central galaxies and the uncertain intracluster light (ICL), {f}{{b,200}} increases by ≈ 0.015, consistent with the cosmic value and therefore no significant baryon loss from the system. The total mass profile is nearly a power law over a large radial range (∼0.2–10 R e ), where the corresponding density slope α obeys the α -{R}e scaling relation for massive early-type galaxies. Performing our analysis in the context of MOND still requires a large DM fraction (85.0 % +/- 2.5 % at r = 100 kpc) similar to that obtained using the standard Newtonian approach. The detection of a plausible stellar BCG mass component distinct from the NFW DM halo in the total gravitational potential suggests that ∼ {10}14 {M}ȯ represents the mass scale above which

  10. The Impact of Baryonic Physics on the Structure of Dark Matter Halos: the View from the FIRE Cosmological Simulations

    Science.gov (United States)

    Keung Chan, Tsang; Keres, Dusan; Oñorbe, Jose; Hopkins, Philip F.; Muratov, Alexander; Faucher-Giguere, Claude-Andre; Quataert, Eliot

    2016-06-01

    We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, which incorporates explicit stellar feedback in the multi-phase ISM, with energetics from stellar population models. We find that stellar feedback, without ``fine-tuned'' parameters, greatly alleviates small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile (α) shows a strong mass dependence: profiles are shallow at Mh ∼ 1010-1011 M⊙ and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. Because the star formation efficiency, Ms/Mh is strongly halo mass dependent, a rapid change in α occurs around Mh ∼1010M⊙, (Ms∼106-107M⊙) as sufficient feedback energy becomes available to perturb the DM. Large cores are not established during the period of rapid growth of halos because of ongoing DM mass accumulation. Instead, cores require several bursts of star formation after the rapid buildup has completed. Stellar feedback dramatically reduces circular velocities in the inner kpc of massive dwarfs; this could be sufficient to explain the ``Too Big To Fail'' problem without invoking non-standard DM. Finally, feedback and baryonic contraction in Milky Way-mass halos produce DM profiles slightly shallower than the Navarro-Frenk-White profile, consistent with the normalization of the observed Tully-Fisher relation.

  11. How Density Environment Changes the Influence of the Dark Matter-Baryon Streaming Velocity on the Cosmological Structure Formation

    CERN Document Server

    Ahn, Kyungjin

    2016-01-01

    We study the dynamical effect of relative velocities between dark matter and baryonic fluids, which remained supersonic after the epoch of recombination. The impact of this supersonic motion on the formation of cosmological structures was first formulated by Tseliakhovich & Hirata (2010), in terms of the linear theory of small-scale fluctuations coupled to large-scale, relative velocities in mean-density regions. In their formalism, they limited the large-scale density environment to be those of the global mean density. We improve on their formulation by allowing variation in the density environment as well as the relative velocities. This leads to a new type of coupling between large-scale and small-scale modes. We find that the small-scale fluctuation grows in a biased way: faster in the overdense environment and slower in the underdense environment. We also find that the net effect on the global power spectrum of the density fluctuation is to boost its overall amplitude from the prediction by Tseliakho...

  12. Compressed Baryonic Matter: from Nuclei to Pulsars

    CERN Document Server

    Xu, Renxin

    2013-01-01

    Our world is wonderful because of the negligible baryonic part although unknown dark matter and dark energy dominate the Universe. Those nuclei in the daily life are forbidden to fuse by compression due to the Coulomb repulse, nevertheless, it is usually unexpected in extraterrestrial extreme-environments: the gravity in a core of massive evolved star is so strong that all the other forces (including the Coulomb one) could be neglected. Compressed baryonic matter is then produced after supernova, manifesting itself as pulsar-like stars observed. The study of this compressed baryonic matter can not only be meaningful in fundamental physics (e.g., the elementary color interaction at low-energy scale, testing gravity theories, detecting nano-Hertz background gravitational waves), but has also profound implications in engineering applications (including time standard and navigation), and additionally, is focused by Chinese advanced telescopes, either terrestrial or in space. Historically, in 1930s, L. Landau spec...

  13. Quirky Composite Dark Matter

    CERN Document Server

    Kribs, Graham D; Terning, John; Zurek, Kathryn M

    2009-01-01

    We propose a new dark matter candidate, quirky dark matter, that is a scalar baryonic bound state of a new non-Abelian force that becomes strong below the electroweak scale. The bound state is made of chiral quirks: new fermions that transform under both the new strong force as well as in a chiral representation of the electroweak group, acquiring mass from the Higgs mechanism. Electric charge neutrality of the lightest baryon requires approximately degenerate quirk masses which also causes the charge radius of the bound state to be negligible. The abundance is determined by an asymmetry that is linked to the baryon and lepton numbers of the universe through electroweak sphalerons. Dark matter elastic scattering with nuclei proceeds through Higgs exchange as well as an electromagnetic polarizability operator which is just now being tested in direct detection experiments. A novel method to search for quirky dark matter is to look for a gamma-ray dark line spectroscopic feature in galaxy clusters that result fr...

  14. Dark world and baryon asymmetry from a common source

    CERN Document Server

    Suematsu, D

    2006-01-01

    We study generation of baryon number asymmetry and both abundance of dark matter and dark energy on the basis of global symmetry and its associating flat directions in a supersymmetric model. We assume the existence of a model independent axion which is generally expected in the effective theory of superstring. If we consider a combined field of the model independent axion and a pseudo Nambu-Goldstone boson coming from spontaneous breaking of the global symmetry, its potential can be sufficiently flat and then it may present a candidate of the dark energy as a quintessential axion. Both the baryon asymmetry and the dark matter are supposed to be produced nonthermally as the asymmetry of another global charge through the Affleck-Dine mechanism along the relevant flat direction. Its decay to the observable and hidden sectors explains the baryon number asymmetry and the dark matter abundance, respectively.

  15. Dark Matter: Introduction

    CERN Document Server

    Rees, Martin J

    2003-01-01

    This short review was prepared as an introduction to the Royal Society's 'Dark Matter' conference. It addresses the embarrassing fact that 95% of the universe is unaccounted for. Favoured dark matter candidates are axions or weakly-interacting particles that have survived from the very early universe, but more exotic options cannot be excluded. Experimental searches are being made for the 'dark' particles but we have indirect clues to their nature too. Comparisons of data (from, eg, gravitational lensing) with numerical simulations of galaxy formation can constrain (eg) the particle velocities and collision cross sections. The mean cosmic density of dark matter (plus baryons) is now pinned down to be only about 30% of the critical density However, other recent evidence -- microwave background anisotropies, complemented by data on distant supernovae -- reveals that our universe actually is 'flat', and that its dominant ingredient (about 70% of the total mass-energy) is something quite unexpected -- 'dark energ...

  16. Lectures on dark matter

    International Nuclear Information System (INIS)

    These lectures concentrate on evolution and generation of dark matter perturbations. The purpose of the lectures is to present, in a systematic way, a comprehensive review of the cosmological parameters that can lead to observable effects in the dark matter clustering properties. We begin by reviewing the relativistic linear perturbation theory formalism. We discuss the gauge issue and derive Einstein's and continuity equations for several popular gauge choices. We continue by developing fluid equations for cold dark matter and baryons and Boltzmann equations for photons, massive and massless neutrinos. We then discuss the generation of initial perturbations by the process of inflation and the parameters of that process that can be extracted from the observations. Finally we discuss evolution of perturbations in various regimes and the imprint of the evolution on the dark matter power spectrum both in the linear and in the nonlinear regime. (author)

  17. Dark Matter and Dark Energy in the Universe

    CERN Document Server

    Turner, M S

    1998-01-01

    For the first time, we have a plausible, complete accounting of matter and energy in the Universe. Expressed a fraction of the critical density it goes like this: neutrinos, between 0.3% and 15%; stars, 0.5%; baryons (total), 5%; matter (total), 40%; smooth, dark energy, 60%; adding up to the critical density. This accounting is consistent with the inflationary prediction of a flat Universe and defines three dark-matter problems: Where are the dark baryons? What is the nonbaryonic dark matter? What is the nature of the dark energy? The leading candidate for the (optically) dark baryons is diffuse hot gas; the leading candidates for the nonbaryonic dark matter are slowly moving elementary particles left over from the earliest moments (cold dark matter), such as axions or neutralinos; the leading candidates for the dark energy involve fundamental physics and include a cosmological constant (vacuum energy), a rolling scalar field (quintessence), and light, frustrated topological defects.

  18. Baryonic matter perturbations in decaying vacuum cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Marttens, R.F. vom; Zimdahl, W. [Departamento de Física, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo (Brazil); Hipólito-Ricaldi, W.S., E-mail: rodrigovonmarttens@gmail.com, E-mail: wiliam.ricaldi@ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br [Departamento de Ciências Naturais, Universidade Federal do Espírito Santo, CEUNES, Rodovia BR 101 Norte, km. 60, CEP 29932-540, São Mateus, Espírito Santo (Brazil)

    2014-08-01

    We consider the perturbation dynamics for the cosmic baryon fluid and determine the corresponding power spectrum for a Λ(t)CDM model in which a cosmological term decays into dark matter linearly with the Hubble rate. The model is tested by a joint analysis of data from supernovae of type Ia (SNIa) (Constitution and Union 2.1), baryonic acoustic oscillations (BAO), the position of the first peak of the anisotropy spectrum of the cosmic microwave background (CMB) and large-scale-structure (LSS) data (SDSS DR7). While the homogeneous and isotropic background dynamics is only marginally influenced by the baryons, there are modifications on the perturbative level if a separately conserved baryon fluid is included. Considering the present baryon fraction as a free parameter, we reproduce the observed abundance of the order of 5% independently of the dark-matter abundance which is of the order of 32% for this model. Generally, the concordance between background and perturbation dynamics is improved if baryons are explicitly taken into account.

  19. The impact of baryonic physics on the structure of dark matter haloes: the view from the FIRE cosmological simulations

    Science.gov (United States)

    Chan, T. K.; Kereš, D.; Oñorbe, J.; Hopkins, P. F.; Muratov, A. L.; Faucher-Giguère, C.-A.; Quataert, E.

    2015-12-01

    We study the distribution of cold dark matter (CDM) in cosmological simulations from the FIRE (Feedback In Realistic Environments) project, for M* ˜ 104-11 M⊙ galaxies in Mh ˜ 109-12 M⊙ haloes. FIRE incorporates explicit stellar feedback in the multiphase interstellar medium, with energetics from stellar population models. We find that stellar feedback, without `fine-tuned' parameters, greatly alleviates small-scale problems in CDM. Feedback causes bursts of star formation and outflows, altering the DM distribution. As a result, the inner slope of the DM halo profile (α) shows a strong mass dependence: profiles are shallow at Mh ˜ 1010-1011 M⊙ and steepen at higher/lower masses. The resulting core sizes and slopes are consistent with observations. This is broadly consistent with previous work using simpler feedback schemes, but we find steeper mass dependence of α, and relatively late growth of cores. Because the star formation efficiency M*/Mh is strongly halo mass dependent, a rapid change in α occurs around Mh ˜ 1010 M⊙ (M* ˜ 106-107 M⊙), as sufficient feedback energy becomes available to perturb the DM. Large cores are not established during the period of rapid growth of haloes because of ongoing DM mass accumulation. Instead, cores require several bursts of star formation after the rapid build-up has completed. Stellar feedback dramatically reduces circular velocities in the inner kpc of massive dwarfs; this could be sufficient to explain the `Too Big To Fail' problem without invoking non-standard DM. Finally, feedback and baryonic contraction in Milky Way-mass haloes produce DM profiles slightly shallower than the Navarro-Frenk-White profile, consistent with the normalization of the observed Tully-Fisher relation.

  20. Reconciliation of MOND and Dark Matter theory

    OpenAIRE

    Chan, Man Ho

    2013-01-01

    I show that Modified Newtonian Dynamics (MOND) is equivalent to assuming an isothermal dark matter density profile, with its density related to the enclosed total baryonic mass. This density profile can be deduced by physical laws if a dark matter core exists and if the baryonic component is spherically-symmetric, isotropic and isothermal. All the usual predictions of MOND, as well as the universal constant $a_0$, can be derived in this model. Since the effects of baryonic matter are larger i...

  1. Constraining the Baryon-Dark Matter Relative Velocity with the Large-Scale 3-Point Correlation Function of the SDSS BOSS DR12 CMASS Galaxies

    CERN Document Server

    Slepian, Zachary; Blazek, Jonathan A; Brownstein, Joel R; Chuang, Chia-Hsun; Gil-Marín, Héctor; Ho, Shirley; Kitaura, Francisco-Shu; McEwen, Joseph E; Percival, Will J; Ross, Ashley J; Rossi, Graziano; Seo, Hee-Jong; Slosar, Anže; Vargas-Magaña, Mariana

    2016-01-01

    We search for a galaxy clustering bias due to a modulation of galaxy number with the baryon-dark matter relative velocity resulting from recombination-era physics. We find no detected signal and place the constraint $b_v < 0.01$ on the relative velocity bias for the CMASS galaxies. This bias is an important potential systematic of Baryon Acoustic Oscillation (BAO) method measurements of the cosmic distance scale using the 2-point clustering. Our limit on the relative velocity bias indicates a systematic shift of no more than $0.3\\%$ rms in the distance scale inferred from the BAO feature in the BOSS 2-point clustering, well below the $1\\%$ statistical error of this measurement. This constraint is the most stringent currently available and has important implications for the ability of upcoming large-scale structure surveys such as DESI to self-protect against the relative velocity as a possible systematic.

  2. Double-Disk Dark Matter

    CERN Document Server

    Fan, JiJi; Randall, Lisa; Reece, Matthew

    2013-01-01

    Based on observational tests and constraints on halo structure, dark matter is generally taken to be cold and essentially collisionless. On the other hand, given the large number of particles and forces in the visible world, a more complex dark sector could be a reasonable or even likely possibility. This hypothesis leads to testable consequences, perhaps portending the discovery of a rich hidden world neighboring our own. We consider a scenario that readily satisfies current bounds that we call Partially Interacting Dark Matter (PIDM). This scenario contains self-interacting dark matter, but it is not the dominant component. Even if PIDM contains only a fraction of the net dark matter density, comparable to the baryonic fraction, the subdominant component's interactions can lead to interesting and potentially observable consequences. Our primary focus will be the special case of Double-Disk Dark Matter (DDDM), in which self-interactions allow the dark matter to lose enough energy to lead to dynamics similar ...

  3. Dark Matter and Dark Energy: The Critical Questions

    OpenAIRE

    Turner, Michael S.

    2002-01-01

    Stars account for only about 0.5% of the content of the Universe; the bulk of the Universe is optically dark. The dark side of the Universe is comprised of: at least 0.1% light neutrinos; 3.5% +/- 1% baryons; 29% +/- 4% cold dark matter; and 66% +/- 6% dark energy. Now that we have characterized the dark side of the Universe, the challenge is to understand it. The critical questions are: (1) What form do the dark baryons take? (2) What is (are) the constituent(s) of the cold dark matter? (3) ...

  4. Asymmetric dark matter from hidden sector baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Bhaskar [Department of Physics and Astronomy, Mitchell Institute for Fundamental Physics, Texas A and M University, College Station, TX 77843 (United States); Kumar, Jason, E-mail: jkumar@hawaii.edu [Department of Physics and Astronomy, University of Hawai' i, Honolulu, HI 96822 (United States)

    2011-05-23

    We consider the production of asymmetric dark matter during hidden sector baryogenesis. We consider a particular supersymmetric model where the dark matter candidate has a number density approximately equal to the baryon number density, with a mass of the same scale as the b, c and {tau}. Both baryon asymmetry and dark matter are created at the same time in this model. We describe collider and direct detection signatures of this model.

  5. Dark baryons and rotation curves

    OpenAIRE

    Burkert, A.; Silk, J.

    1997-01-01

    The best measured rotation curve for any galaxy is that of the dwarf spiralXXXX DDO 154, which extends out to about 20 disk scale lengths. It provides an ideal laboratory for testing the universal density profile prediction from high resolution numerical simulations of hierarchical clustering in cold dark matter dominated cosmological models. We find that the observed rotation curve cannot be fit either at small radii, as previously noted, or at large radii. We advocate a resolution of this d...

  6. Dark matter.

    Science.gov (United States)

    Peebles, P James E

    2015-10-01

    The evidence for the dark matter (DM) of the hot big bang cosmology is about as good as it gets in natural science. The exploration of its nature is now led by direct and indirect detection experiments, to be complemented by advances in the full range of cosmological tests, including judicious consideration of the rich phenomenology of galaxies. The results may confirm ideas about DM already under discussion. If we are lucky, we also will be surprised once again. PMID:24794526

  7. The origin of dark matter, matter-anti-matter asymmetry, and inflation

    CERN Document Server

    Mazumdar, Anupam

    2011-01-01

    A rapid phase of accelerated expansion in the early universe, known as inflation, dilutes all matter except the vacuum induced quantum fluctuations. These are responsible for seeding the initial perturbations in the baryonic matter, the non-baryonic dark matter and the observed temperature anisotropy in the cosmic microwave background (CMB) radiation. To explain the universe observed today, the end of inflation must also excite a thermal bath filled with baryons, an amount of baryon asymmetry, and dark matter. We review the current understanding of inflation, dark matter, mechanisms for generating matter-anti-matter asymmetry, and the prospects for testing them at ground and space based experiments.

  8. Interactions between dark energy and dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, Marco

    2009-03-20

    We have investigated interacting dark energy cosmologies both concerning their impact on the background evolution of the Universe and their effects on cosmological structure growth. For the former aspect, we have developed a cosmological model featuring a matter species consisting of particles with a mass that increases with time. In such model the appearance of a Growing Matter component, which is negligible in early cosmology, dramatically slows down the evolution of the dark energy scalar field at a redshift around six, and triggers the onset of the accelerated expansion of the Universe, therefore addressing the Coincidence Problem. We propose to identify this Growing Matter component with cosmic neutrinos, in which case the present dark energy density can be related to the measured average mass of neutrinos. For the latter aspect, we have implemented the new physical features of interacting dark energy models into the cosmological N-body code GADGET-2, and we present the results of a series of high-resolution simulations for a simple realization of dark energy interaction. As a consequence of the new physics, cold dark matter and baryon distributions evolve differently both in the linear and in the non-linear regime of structure formation. Already on large scales, a linear bias develops between these two components, which is further enhanced by the non-linear evolution. We also find, in contrast with previous work, that the density profiles of cold dark matter halos are less concentrated in coupled dark energy cosmologies compared with {lambda}{sub CDM}. Also, the baryon fraction in halos in the coupled models is significantly reduced below the universal baryon fraction. These features alleviate tensions between observations and the {lambda}{sub CDM} model on small scales. Our methodology is ideally suited to explore the predictions of coupled dark energy models in the fully non-linear regime, which can provide powerful constraints for the viable parameter

  9. Interactions between dark energy and dark matter

    International Nuclear Information System (INIS)

    We have investigated interacting dark energy cosmologies both concerning their impact on the background evolution of the Universe and their effects on cosmological structure growth. For the former aspect, we have developed a cosmological model featuring a matter species consisting of particles with a mass that increases with time. In such model the appearance of a Growing Matter component, which is negligible in early cosmology, dramatically slows down the evolution of the dark energy scalar field at a redshift around six, and triggers the onset of the accelerated expansion of the Universe, therefore addressing the Coincidence Problem. We propose to identify this Growing Matter component with cosmic neutrinos, in which case the present dark energy density can be related to the measured average mass of neutrinos. For the latter aspect, we have implemented the new physical features of interacting dark energy models into the cosmological N-body code GADGET-2, and we present the results of a series of high-resolution simulations for a simple realization of dark energy interaction. As a consequence of the new physics, cold dark matter and baryon distributions evolve differently both in the linear and in the non-linear regime of structure formation. Already on large scales, a linear bias develops between these two components, which is further enhanced by the non-linear evolution. We also find, in contrast with previous work, that the density profiles of cold dark matter halos are less concentrated in coupled dark energy cosmologies compared with ΛCDM. Also, the baryon fraction in halos in the coupled models is significantly reduced below the universal baryon fraction. These features alleviate tensions between observations and the ΛCDM model on small scales. Our methodology is ideally suited to explore the predictions of coupled dark energy models in the fully non-linear regime, which can provide powerful constraints for the viable parameter space of such scenarios

  10. Dark Energy and Dark Matter

    OpenAIRE

    Olive, Keith A.

    2010-01-01

    A brief overview of our current understanding of abundance and properties of dark energy and dark matter is presented. A more focused discussion of supersymmetric dark matter follows. Included is a frequentist approach to the supersymmetric parameter space and consequences for the direct detection of dark matter.

  11. LSP as a Candidate for Dark Matter

    OpenAIRE

    Lahanas, A.B.

    2006-01-01

    The most recent observations by the WMAP satellite provided us with data of unprecedented accuracy regarding the parameters describing the Standard Cosmological Model. The current matter-energy density of the Universe is close to its critical value of which 73% is attributed to Dark Energy, 23% to Cold Dark Matter and only 4% is ordinary matter of baryonic nature. The origins of the Dark Energy (DE) and Dark Matter (DM) constitute the biggest challenge of Modern Astroparticle Physics. Particl...

  12. Asymmetric WIMP dark matter

    OpenAIRE

    Graesser, Michael L.; Shoemaker, Ian M.; Vecchi, Luca

    2011-01-01

    In existing dark matter models with global symmetries the relic abundance of dark matter is either equal to that of anti-dark matter (thermal WIMP), or vastly larger, with essentially no remaining anti-dark matter (asymmetric dark matter). By exploring the consequences of a primordial asymmetry on the coupled dark matter and anti-dark matter Boltzmann equations we find large regions of parameter space that interpolate between these two extremes. Interestingly, this new asymmetric WIMP framewo...

  13. Dark Matter Superfluidity

    CERN Document Server

    Khoury, Justin

    2016-01-01

    In this talk I summarize a novel framework that unifies the stunning success of MOND on galactic scales with the triumph of the $\\Lambda$CDM model on cosmological scales. This is achieved through the rich and well-studied physics of superfluidity. The dark matter and MOND components have a common origin, representing different phases of a single underlying substance. In galaxies, dark matter thermalizes and condenses to form a superfluid phase. The superfluid phonons couple to baryonic matter particles and mediate a MOND-like force. This framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): dark matter has a higher temperature in clusters, and hence is in a mixture of superfluid and normal phase. The rich and well-studied physics of superfluidity leads to a number of striking observational signatures, which we briefly discuss. Remarkably the critical temperature and equation of state of the dark matter superfluid are similar to those of known co...

  14. A Dark Matter Superfluid

    CERN Document Server

    Khoury, Justin

    2015-01-01

    In this talk we present a novel framework that unifies the stunning success of MOND on galactic scales with the triumph of the LambdaCDM model on cosmological scales. This is achieved through the rich and well-studied physics of superfluidity. The dark matter and MOND components have a common origin, representing different phases of a single underlying substance. In galaxies, dark matter thermalizes and condenses to form a superfluid phase. The superfluid phonons couple to baryonic matter particles and mediate a MOND-like force. Our framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): dark matter has a higher temperature in clusters, and hence is in a mixture of superfluid and normal phase. The rich and well-studied physics of superfluidity leads to a number of striking observational signatures, which we briefly discuss. Remarkably the critical temperature and equation of state of the dark matter superfluid are similar to those of known cold at...

  15. Visible and Dark Matter Genesis and Cosmic Positron/Electron Excesses

    OpenAIRE

    Gu, Pei-Hong; Sarkar, Utpal; Zhang, Xinmin

    2009-01-01

    Dark and baryonic matter contribute comparable energy density to the present Universe. The dark matter may also be responsible for the cosmic positron/electron excesses. We connect these phenomena with Dirac seesaw for neutrino masses. In our model (i) the dark matter relic density is a dark matter asymmetry generated simultaneously with the baryon asymmetry so that we can naturally understand the coincidence between the dark and baryonic matter; (ii) the dark matter mostly decays into the le...

  16. Dark matter and dark energy

    CERN Multimedia

    Caldwell, Robert

    2009-01-01

    "Observations continue to indicate that the Universe is dominated by invisible components - dark matter and dark energy. Shedding light on this cosmic darkness is a priority for astronomers and physicists" (3 pages)

  17. Lectures on Dark Matter Physics

    CERN Document Server

    Lisanti, Mariangela

    2016-01-01

    Rotation curve measurements from the 1970s provided the first strong indication that a significant fraction of matter in the Universe is non-baryonic. In the intervening years, a tremendous amount of progress has been made on both the theoretical and experimental fronts in the search for this missing matter, which we now know constitutes nearly 85% of the Universe's matter density. These series of lectures, first given at the TASI 2015 summer school, provide an introduction to the basics of dark matter physics. They are geared for the advanced undergraduate or graduate student interested in pursuing research in high-energy physics. The primary goal is to build an understanding of how observations constrain the assumptions that can be made about the astro- and particle physics properties of dark matter. The lectures begin by delineating the basic assumptions that can be inferred about dark matter from rotation curves. A detailed discussion of thermal dark matter follows, motivating Weakly Interacting Massive P...

  18. Dark matter: an overview of direct searches

    International Nuclear Information System (INIS)

    The purpose of this paper, intended for physicists 'in collision', is to give a flavour of the experimental challenges raised by the detection of Dark Matter. It summarizes the detection methods of the MACHO's, celestial bodies candidate for the baryonic Dark Matter and of the WIMP's, particles candidate for the non-baryonic Dark Matter. Current status and hopes are given. Two side aspects not directly related to the experimental search will be evoked to illustrate that the Dark Matter puzzle is indeed at the common frontier of various fields of physics. (author)

  19. Can dark matter see itself?

    CERN Document Server

    Hannestad, S

    2000-01-01

    Many independent high-resolution simulations of structure formation in cold dark matter models show that galactic halos should have singular core profiles. This is in stark contrast with observations of both low- and high-surface brightness galaxies, which indicate that the dark matter has almost constant density in the central parts of halos. Basically there are three possible avenues to a solution to the problem, which we discuss in turn. Observations of halo profiles could be more uncertain than previously thought, and higher resolution observations could reveal that spirals do have a singular core feature. The highest resolution simulations do not include a baryonic component, and it is conceivable that violent star formation processes and similar phenomena can destroy the singular dark matter core and lead to an almost constant density core profile. Finally, we discuss in more detail the intriguing possibility that the discrepancy hints at some new exotic physics of the dark matter. Warm dark matter and ...

  20. Dark matter from Affleck-Dine baryogenesis

    OpenAIRE

    Kusenko, Alexander

    1999-01-01

    Fragmentation of the Affleck-Dine condensate into Q-balls could fill the Universe with dark matter either in the form of stable baryonic balls, or LSP produced from the decay of unstable Q-balls. The dark matter and the ordinary matter in the Universe may share the same origin.

  1. Reconciling MOND and dark matter?

    International Nuclear Information System (INIS)

    Observations of galaxies suggest a one-to-one analytic relation between the inferred gravity of dark matter at any radius and the enclosed baryonic mass, a relation summarized by Milgrom's law of modified Newtonian dynamics (MOND). However, present-day covariant versions of MOND usually require some additional fields contributing to the geometry, as well as an additional hot dark matter component to explain cluster dynamics and cosmology. Here, we envisage a slightly more mundane explanation, suggesting that dark matter does exist but is the source of MOND-like phenomenology in galaxies. We assume a canonical action for dark matter, but also add an interaction term between baryonic matter, gravity, and dark matter, such that standard matter effectively obeys the MOND field equation in galaxies. We show that even the simplest realization of the framework leads to a model which reproduces some phenomenological predictions of cold dark matter (CDM) and MOND at those scales where these are most successful. We also devise a more general form of the interaction term, introducing the medium density as a new order parameter. This allows for new physical effects which should be amenable to observational tests in the near future. Hence, this very general framework, which can be furthermore related to a generalized scalar-tensor theory, opens the way to a possible unification of the successes of CDM and MOND at different scales

  2. The Entire Virial Radius of the Fossil Cluster RXJ1159+5531: II. Dark Matter and Baryon Fraction

    OpenAIRE

    Buote, David A.; Su, Yuanyuan; Gastaldello, Fabio; Brighenti, Fabrizio

    2016-01-01

    In this second paper on the entire virial region of the relaxed fossil cluster RXJ1159+5531, we present a hydrostatic analysis of the hot intracluster medium (ICM). For a model consisting of ICM, stellar mass from the central galaxy (BCG), and an NFW dark matter (DM) halo, we obtain good descriptions of the projected radial profiles of ICM emissivity and temperature. The BCG stellar mass is clearly detected with M_star/L_K = 0.61 +/- 0.11 solar, consistent with stellar population synthesis mo...

  3. Fermion Portal Dark Matter

    OpenAIRE

    Bai, Yang; Berger, Joshua(SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA)

    2013-01-01

    We study a class of simplified dark matter models in which one dark matter particle couples with a mediator and a Standard Model fermion. In such models, collider and direct detection searches probe complimentary regions of parameter space. For Majorana dark matter, direct detection covers the region near mediator-dark matter degeneracy, while colliders probe regions with a large dark matter and mediator mass splitting. For Dirac and complex dark matter, direct detection is effective for the ...

  4. The Variation of Rotation Curve Shapes as a Signature of the Effects of Baryons on Dark Matter Density Profiles

    CERN Document Server

    Brook, Chris

    2015-01-01

    Rotation curves of galaxies show a wide range of shapes, which can be paramaterized as scatter in Vrot(1kpc)/Vmax i.e.the ratio of the rotation velocity measured at 1kpc and the maximum measured rotation velocity. We examine whether the observed scatter can be accounted for by combining scatters in disc scale-lengths, the concentration-halo mass relation, and the Mstar-Mhalo relation. We use these scatters to create model galaxy populations; when housed within dark matter halos that have universal, NFW density profiles, the model does not match the lowest observed values of Vrot(1kpc)/Vmax and has too little scatter in Vrot(1kpc)/Vmax compared to observations. By contrast, a model using a mass dependant dark matter profile, where the inner slope is determined by the ratio of Mstar/Mhalo, produces galaxies with low values of Vrot(1kpc)/Vmax and a much larger scatter, both in agreement with observation. We conclude that the large observed scatter in Vrot(1kpc)/Vmax favours density profiles that are significantl...

  5. Dark matter and the equivalence principle

    Science.gov (United States)

    Frieman, Joshua A.; Gradwohl, Ben-Ami

    1993-01-01

    A survey is presented of the current understanding of dark matter invoked by astrophysical theory and cosmology. Einstein's equivalence principle asserts that local measurements cannot distinguish a system at rest in a gravitational field from one that is in uniform acceleration in empty space. Recent test-methods for the equivalence principle are presently discussed as bases for testing of dark matter scenarios involving the long-range forces between either baryonic or nonbaryonic dark matter and ordinary matter.

  6. Dark Energy and Dark Matter

    OpenAIRE

    Comelli, D.; Pietroni, M.; Riotto, A.

    2003-01-01

    It is a puzzle why the densities of dark matter and dark energy are nearly equal today when they scale so differently during the expansion of the universe. This conundrum may be solved if there is a coupling between the two dark sectors. In this paper we assume that dark matter is made of cold relics with masses depending exponentially on the scalar field associated to dark energy. Since the dynamics of the system is dominated by an attractor solution, the dark matter particle mass is forced ...

  7. Dark Matter Annihilation at the Galactic Center

    Energy Technology Data Exchange (ETDEWEB)

    Linden, Timothy Ryan [Univ. of California, Santa Cruz, CA (United States)

    2013-06-01

    Observations by the WMAP and PLANCK satellites have provided extraordinarily accurate observations on the densities of baryonic matter, dark matter, and dark energy in the universe. These observations indicate that our universe is composed of approximately ve times as much dark matter as baryonic matter. However, e orts to detect a particle responsible for the energy density of dark matter have been unsuccessful. Theoretical models have indicated that a leading candidate for the dark matter is the lightest supersymmetric particle, which may be stable due to a conserved R-parity. This dark matter particle would still be capable of interacting with baryons via weak-force interactions in the early universe, a process which was found to naturally explain the observed relic abundance of dark matter today. These residual annihilations can persist, albeit at a much lower rate, in the present universe, providing a detectable signal from dark matter annihilation events which occur throughout the universe. Simulations calculating the distribution of dark matter in our galaxy almost universally predict the galactic center of the Milky Way Galaxy (GC) to provide the brightest signal from dark matter annihilation due to its relative proximity and large simulated dark matter density. Recent advances in telescope technology have allowed for the rst multiwavelength analysis of the GC, with suitable e ective exposure, angular resolution, and energy resolution in order to detect dark matter particles with properties similar to those predicted by the WIMP miracle. In this work, I describe ongoing e orts which have successfully detected an excess in -ray emission from the region immediately surrounding the GC, which is di cult to describe in terms of standard di use emission predicted in the GC region. While the jury is still out on any dark matter interpretation of this excess, I describe several related observations which may indicate a dark matter origin. Finally, I discuss the

  8. Galilean Equivalence for Galactic Dark Matter

    CERN Document Server

    Kesden, M; Kesden, Michael; Kamionkowski, Marc

    2006-01-01

    Satellite galaxies of the Milky Way experience a tidal disruption as they orbit in the Milky Way's dark halo. While the bound core of the satellite remains dominated by dark matter, the tidally disrupted stars behave like purely baryonic tracers of the Milky Way's potential well. If dark matter experiences a stronger self attraction than visible matter, stars will preferentially gain rather than lose energy during tidal disruption. This leads to a relative enhancement in the trailing as compared to the leading tidal stream. We show that the absence of a strong asymmetry in the surface brightness of the leading and trailing tidal streams already constrains the equivalence of acceleration of dark matter and baryons in a gravitational field to less than ten percent--thus ruling out a recently proposed mechanism to clear dwarf galaxies from voids. Future observations should be sensitive at the percent level to departures from the equivalence of dark matter and baryons.

  9. THE TEMPERATURE OF HOT GAS IN GALAXIES AND CLUSTERS: BARYONS DANCING TO THE TUNE OF DARK MATTER

    International Nuclear Information System (INIS)

    The temperature profile of hot gas in galaxies and galaxy clusters is largely determined by the depth of the total gravitational potential and thereby by the dark matter (DM) distribution. We use high-resolution hydrodynamical simulations of galaxy formation to derive a surprisingly simple relation between the gas temperature and DM properties. We show that this relation holds not just for galaxy clusters but also for equilibrated and relaxed galaxies at radii beyond the central stellar-dominated region of typically a few kpc. It is then clarified how a measurement of the temperature and density of the hot gas component can lead to an indirect measurement of the DM velocity anisotropy in galaxies. We also study the temperature relation for galaxy clusters in the presence of self-regulated, recurrent active galactic nuclei (AGNs), and demonstrate that this temperature relation even holds outside the inner region of ∼30 kpc in clusters with an active AGN.

  10. The temperature of hot gas in galaxies and clusters: baryons dancing to the tune of dark matter

    CERN Document Server

    Hansen, Steen H; Romano-Diaz, Emilio; Hoffman, Yehuda; Brüggen, Marcus; Scannapieco, Evan; Stinson, Greg S

    2010-01-01

    The temperature profile of hot gas in galaxies and galaxy clusters is largely determined by the depth of the total gravitational potential and thereby by the dark matter (DM) distribution. We use high-resolution hydrodynamical simulations of galaxy formation to derive a surprisingly simple relation between the gas temperature and DM properties. We show that this relation holds not just for galaxy clusters but also for equilibrated and relaxed galaxies at radii beyond the central stellar-dominated region of typically a few kpc. It is then clarified how a measurement of the temperature and density of the hot gas component can lead to an indirect measurement of the DM velocity anisotropy in galaxies. We also study the temperature relation for galaxy clusters in the presence of self-regulated, recurrent active galactic nuclei (AGN), and demonstrate that this temperature relation even holds outside the inner region of 30 kpc in clusters with an active AGN.

  11. Dark matter candidates

    International Nuclear Information System (INIS)

    One of the simplest, yet most profound, questions we can ask about the Universe is, how much stuff is in it, and further what is that stuff composed of? Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation. Remarkably, at this late date in the history of the Universe we still do not have a definitive answer to this simplest of questions---although we have some very intriguing clues. It is known with certainty that most of the material in the Universe is dark, and we have the strong suspicion that the dominant component of material in the Cosmos is not baryons, but rather is exotic relic elementary particles left over from the earliest, very hot epoch of the Universe. If true, the Dark Matter question is a most fundamental one facing both particle physics and cosmology. The leading particle dark matter candidates are: the axion, the neutralino, and a light neutrino species. All three candidates are accessible to experimental tests, and experiments are now in progress. In addition, there are several dark horse, long shot, candidates, including the superheavy magnetic monopole and soliton stars. 13 refs

  12. Light asymmetric dark matter from new strong dynamics

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Sarkar, Subir; Schmidt-Hoberg, Kai

    2011-01-01

    A ~5 GeV `dark baryon' with a cosmic asymmetry similar to that of baryons is a natural candidate for the dark matter. We study the possibility of generating such a state through dynamical electroweak symmetry breaking, and show that it can share the relic baryon asymmetry via sphaleron interactions...

  13. Double-Disk Dark Matter

    Science.gov (United States)

    Fan, JiJi; Katz, Andrey; Randall, Lisa; Reece, Matthew

    2013-09-01

    Based on observational tests of large scale structure and constraints on halo structure, dark matter is generally taken to be cold and essentially collisionless. On the other hand, given the large number of particles and forces in the visible world, a more complex dark sector could be a reasonable or even likely possibility. This hypothesis leads to testable consequences, perhaps portending the discovery of a rich hidden world neighboring our own. We consider a scenario that readily satisfies current bounds that we call Partially Interacting Dark Matter (PIDM). This scenario contains self-interacting dark matter, but it is not the dominant component. Even if PIDM contains only a fraction of the net dark matter density, comparable to the baryonic fraction, the subdominant component’s interactions can lead to interesting and potentially observable consequences. Our primary focus will be the special case of Double-Disk Dark Matter (DDDM), in which self-interactions allow the dark matter to lose enough energy to lead to dynamics similar to those in the baryonic sector. We explore a simple model in which DDDM can cool efficiently and form a disk within galaxies, and we evaluate some of the possible observational signatures. The most prominent signal of such a scenario could be an enhanced indirect detection signature with a distinctive spatial distribution. Even though subdominant, the enhanced density at the center of the galaxy and possibly throughout the plane of the galaxy (depending on precise alignment) can lead to large boost factors, and could even explain a signature as large as the 130 GeV Fermi line. Such scenarios also predict additional dark radiation degrees of freedom that could soon be detectable and would influence the interpretation of future data, such as that from Planck and from the Gaia satellite. We consider this to be the first step toward exploring a rich array of new possibilities for dark matter dynamics.

  14. Dark matter: Models and detection methods

    International Nuclear Information System (INIS)

    The need for dark matter is briefly reviewed. A wealth of observational information points to the existence of a non-baryonic component. To the theoretically favoured candidates today belong axions, supersymmetric particles, and in a smaller quantity, massive neutrinos. The theoretical foundation and experimental situation for each of these is reviewed. In particular, indirect detection methods of supersymmetric dark matter are described. Aspects of the density structure of dark matter halos, important for estimating the chances of detection, are discussed

  15. Asymmetric Dark Matter and Dark Radiation

    CERN Document Server

    Blennow, Mattias; Mena, Olga; Redondo, Javier; Serra, Paolo

    2012-01-01

    Asymmetric Dark Matter (ADM) models invoke a particle-antiparticle asymmetry, similar to the one observed in the Baryon sector, to account for the Dark Matter (DM) abundance. Both asymmetries are usually generated by the same mechanism and generally related, thus predicting DM masses around 5 GeV in order to obtain the correct density. The main challenge for successful models is to ensure efficient annihilation of the thermally produced symmetric component of such a light DM candidate without violating constraints from collider or direct searches. A common way to overcome this involves a light mediator, into which DM can efficiently annihilate and which subsequently decays into Standard Model particles. Here we explore the scenario where the light mediator decays instead into lighter degrees of freedom in the dark sector that act as radiation in the early Universe. While this assumption makes indirect DM searches challenging, it leads to signals of extra radiation at BBN and CMB. Under certain conditions, pre...

  16. Dark Matter

    Science.gov (United States)

    Lincoln, Don

    2013-01-01

    It's a dark, dark universe out there, and I don't mean because the night sky is black. After all, once you leave the shadow of the Earth and get out into space, you're surrounded by countless lights glittering everywhere you look. But for all of Sagan's billions and billions of stars and galaxies, it's a jaw-dropping fact that the ordinary kind of…

  17. Dark Group: Dark Energy and Dark Matter

    OpenAIRE

    de la Macorra, Axel

    2002-01-01

    We study the possibility that a dark group, a gauge group with particles interacting with the standard model particles only via gravity, is responsible for containing the dark energy and dark matter required by present day observations. We show that it is indeed possible and we determine the constrains for the dark group. The non-perturbative effects generated by a strong gauge coupling constant can de determined and a inverse power law scalar potential IPL for the dark meson fields is genera...

  18. Twin Higgs Asymmetric Dark Matter.

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-18

    We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20  GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors. PMID:26430985

  19. Secretly Asymmetric Dark Matter

    OpenAIRE

    Agrawal, Prateek; Kilic, Can; Swaminathan, Sivaramakrishnan; Trendafilova, Cynthia

    2016-01-01

    We study a mechanism where the dark matter number density today arises from asymmetries generated in the dark sector in the early universe, even though total dark matter number remains zero throughout the history of the universe. The dark matter population today can be completely symmetric, with annihilation rates above those expected from thermal WIMPs. We give a simple example of this mechanism using a benchmark model of flavored dark matter. We discuss the experimental signatures of this s...

  20. Constraints on Dark Matter interactions from structure formation: Damping lengths

    OpenAIRE

    Boehm, Celine; Schaeffer, Richard

    2004-01-01

    (Shortened) Weakly Interacting Massive Particles are often said to be the best Dark Matter candidates. Studies have shown however that rather large Dark Matter-photon or Dark Matter-baryon interactions could be allowed by cosmology. Here we address the question of the role of the Dark Matter interactions in more detail to determine at which extent Dark Matter has to be necessarily weakly interacting. To this purpose, we compute the collisional damping (and free-streaming) lengths of generic i...

  1. Originally Asymmetric Dark Matter

    OpenAIRE

    Okada, Nobuchika; Seto, Osamu

    2012-01-01

    We propose a scenario with a fermion dark matter, where the dark matter particle used to be the Dirac fermion, but it takes the form of the Majorana fermion at a late time. The relic number density of the dark matter is determined by the dark matter asymmetry generated through the same mechanism as leptogenesis when the dark matter was the Dirac fermion. After efficient dark matter annihilation processes have frozen out, a phase transition of a scalar field takes place and generates Majorana ...

  2. Dark Matter and Energy in the Universe

    CERN Document Server

    Turner, M S

    2000-01-01

    For the first time, we have a plausible and complete accounting of matter and energy in the Universe. Expressed a fraction of the critical density it goes like this: neutrinos, between 0.3% and 15%; stars, between 0.3% and 0.6%; baryons (total), 5% +/- 0.5%; matter (total), 40% +/- 10%; smooth, dark energy, 80% +/- 20%; totaling to the critical density (within the errors). This accounting is consistent with the inflationary prediction of a flat Universe and defines three dark-matter problems: Where are the dark baryons? What is the nonbaryonic dark matter? What is the nature of the dark energy? The leading candidate for the (optically) dark baryons is diffuse hot gas; the leading candidates for the nonbaryonic dark matter are slowly moving elementary particles left over from the earliest moments (cold dark matter), such as axions or neutralinos; the leading candidates for the dark energy involve fundamental physics and include a cosmological constant (vacuum energy), a rolling scalar field (quintessence), and...

  3. The Effect of Central Baryonic Cores in Dark Halos on the Evaluation of Strong Lensing Probabilities

    Institute of Scientific and Technical Information of China (English)

    Jie Wang

    2004-01-01

    We present an estimate of the strong lensing probability by dark halos, with emphasis on the role of the baryonic matter arising purely from radiative cooling. We treat the contribution of the cooled baryons optimistically with all the cooled baryons confined within a central core, and including no feedback process from stellar evolution. Our two-component model provides a strong lensing probability that is in good agreement with the observed distribution of multiple images of quasars, provided that the cooled baryons are deposited within a spherical region of radius of 0.1 times the virial radius and follow an isothermal profile. It is pointed out that strong lensing may be used as an additional probe of baryon physics in dark halos though this may meanwhile complicate the test of the inner density profiles of dark matter in halos using the observed strong lensing probability.

  4. Secretly Asymmetric Dark Matter

    CERN Document Server

    Agrawal, Prateek; Swaminathan, Sivaramakrishnan; Trendafilova, Cynthia

    2016-01-01

    We study a mechanism where the dark matter number density today arises from asymmetries generated in the dark sector in the early universe, even though total dark matter number remains zero throughout the history of the universe. The dark matter population today can be completely symmetric, with annihilation rates above those expected from thermal WIMPs. We give a simple example of this mechanism using a benchmark model of flavored dark matter. We discuss the experimental signatures of this setup, which arise mainly from the sector that annihilates the symmetric component of dark matter.

  5. Heavy spin-2 Dark Matter

    CERN Document Server

    Babichev, Eugeny; Raidal, Martti; Schmidt-May, Angnis; Urban, Federico; Veermäe, Hardi; von Strauss, Mikael

    2016-01-01

    We provide further details on a recent proposal addressing the nature of the dark sectors in cosmology and demonstrate that all current observations related to Dark Matter can be explained by the presence of a heavy spin-2 particle. Massive spin-2 fields and their gravitational interactions are uniquely described by ghost-free bimetric theory, which is a minimal and natural extension of General Relativity. In this setup, the largeness of the physical Planck mass is naturally related to extremely weak couplings of the heavy spin-2 field to baryonic matter and therefore explains the absence of signals in experiments dedicated to Dark Matter searches. It also ensures the phenomenological viability of our model as we confirm by comparing it with cosmological and local tests of gravity. At the same time, the spin-2 field possesses standard gravitational interactions and it decays universally into all Standard Model fields but not into massless gravitons. Matching the measured DM abundance together with the require...

  6. Cannibal Dark Matter

    CERN Document Server

    Pappadopulo, Duccio; Trevisan, Gabriele

    2016-01-01

    A thermally decoupled hidden sector of particles, with a mass gap, generically enters a phase of cannibalism in the early Universe. The Standard Model sector becomes exponentially colder than the hidden sector. We propose the Cannibal Dark Matter framework, where dark matter resides in a cannibalizing sector with a relic density set by 2-to-2 annihilations. Observable signals of Cannibal Dark Matter include a boosted rate for indirect detection, new relativistic degrees of freedom, and warm dark matter.

  7. Dark Matter Effective Theory

    DEFF Research Database (Denmark)

    Del Nobile, Eugenio; Sannino, Francesco

    2012-01-01

    We organize the effective (self)interaction terms for complex scalar dark matter candidates which are either an isosinglet, isodoublet or an isotriplet with respect to the weak interactions. The classification has been performed ordering the operators in inverse powers of the dark matter cutoff...... scale. We assume Lorentz invariance, color and charge neutrality. We also introduce potentially interesting dark matter induced flavor-changing operators. Our general framework allows for model independent investigations of dark matter properties....

  8. Mirror dark matter discovered?

    OpenAIRE

    Silagadze, Z. K.

    2008-01-01

    Recent astrophysical data indicates that dark matter shows a controversial behaviour in galaxy cluster collisions. In case of the notorious Bullet cluster, dark matter component of the cluster behaves like a collisionless system. However, its behaviour in the Abell 520 cluster indicates a significant self-interaction cross-section. It is hard for the WIMP based dark matter models to reconcile such a diverse behaviour. Mirror dark matter models, on the contrary, are more flexible and for them ...

  9. Dark matter direct detection

    International Nuclear Information System (INIS)

    There are now enough pieces of (gravitational or cosmological) evidence for the existence of dark matter in the universe. The dark matter is an unknown matter that do not emit any electromagnetic radiation and perhaps have very feeble interaction with other particles. It is now established from the study of anisotropies in apparently smooth cosmic microwave background radiation that about 26.5% of the content of the universe is made up of dark matter as compared to only a paltry amount of about 4.5% of known matter. Although the evidence of dark matter is so far gravitational by and large, there are now worldwide endeavours to detect the dark matter directly in the laboratories. The direct detection of dark matter is based on measuring the recoil energy of the nucleus that scatters off a possible dark matter particle that may happen to interact with a nucleus of the detecting material

  10. Nonthermal Supermassive Dark Matter

    Science.gov (United States)

    Chung, Daniel J. H.; Kolb, Edward W.; Riotto, Antonio

    1999-01-01

    We discuss several cosmological production mechanisms for nonthermal supermassive dark matter and argue that dark matter may he elementary particles of mass much greater than the weak scale. Searches for dark matter should ma be limited to weakly interacting particles with mass of the order of the weak scale, but should extend into the supermassive range as well.

  11. WIMPless Dark Matter

    OpenAIRE

    Feng, Jonathan L.; Kumar, Jason

    2009-01-01

    We describe the scenario of WIMPless dark matter. In this scenario of gauge-mediated supersymmetry breaking, a dark matter candidate in the hidden sector is found to naturally have approximately the right relic density to explain astronomical dark matter observations, but with a wide range of possible masses.

  12. Is Cold Dark Matter a Vacuum Effect?

    Science.gov (United States)

    Houlden, Michael A.

    Current theories about the Universe based on an FLRW model conclude that it is composed of ~4% normal matter, ~28 % dark matter and ~68% Dark Energy which is responsible for the well-established accelerated expansion: this model works extremely well. As the Universe expands the density of normal and dark matter decreases while the proportion of Dark Energy increases. This model assumes that the amount of dark matter, whose nature at present is totally unknown, has remained constant. This is a natural assumption if dark matter is a particle of some kind - WIMP, sterile neutrino, lightest supersysmmetric particle or axion, etc. - that must have emerged from the early high temperature phase of the Big Bang. This paper proposes that dark matter is not a particle such as these but a vacuum effect, and that the proportion of dark matter in the Universe is actually increasing with time. The idea that led to this suggestion was that a quantum process (possibly the Higgs mechanism) might operate in the nilpotent vacuum that Rowlands postulates is a dual space to the real space where Standard Model fundamental fermions (and we) reside. This could produce a vacuum quantum state that has mass, which interacts gravitationally, and such states would be `dark matter'. It is proposed that the rate of production of dark matter by this process might depend on local circumstances, such as the density of dark matter and/or normal matter. This proposal makes the testable prediction that the ratio of baryonic to dark matter varies with redshift and offers an explanation, within the framework of Rowlands' ideas, of the coincidence problem - why has cosmic acceleration started in the recent epoch at redshift z ~0.55 when the Dark Energy density first became equal to the matter density?. This process also offers a potential solution to the `missing baryon' problem.

  13. Impeded Dark Matter

    CERN Document Server

    Kopp, Joachim; Slatyer, Tracy R; Wang, Xiao-Ping; Xue, Wei

    2016-01-01

    We consider a new class of thermal dark matter models, dubbed "Impeded Dark Matter", in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. We demonstrate that either case can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppress...

  14. Dark energy and extended dark matter halos

    Science.gov (United States)

    Chernin, A. D.; Teerikorpi, P.; Valtonen, M. J.; Dolgachev, V. P.; Domozhilova, L. M.; Byrd, G. G.

    2012-03-01

    The cosmological mean matter (dark and baryonic) density measured in the units of the critical density is Ωm = 0.27. Independently, the local mean density is estimated to be Ωloc = 0.08-0.23 from recent data on galaxy groups at redshifts up to z = 0.01-0.03 (as published by Crook et al. 2007, ApJ, 655, 790 and Makarov & Karachentsev 2011, MNRAS, 412, 2498). If the lower values of Ωloc are reliable, as Makarov & Karachentsev and some other observers prefer, does this mean that the Local Universe of 100-300 Mpc across is an underdensity in the cosmic matter distribution? Or could it nevertheless be representative of the mean cosmic density or even be an overdensity due to the Local Supercluster therein. We focus on dark matter halos of groups of galaxies and check how much dark mass the invisible outer layers of the halos are able to host. The outer layers are usually devoid of bright galaxies and cannot be seen at large distances. The key factor which bounds the size of an isolated halo is the local antigravity produced by the omnipresent background of dark energy. A gravitationally bound halo does not extend beyond the zero-gravity surface where the gravity of matter and the antigravity of dark energy balance, thus defining a natural upper size of a system. We use our theory of local dynamical effects of dark energy to estimate the maximal sizes and masses of the extended dark halos. Using data from three recent catalogs of galaxy groups, we show that the calculated mass bounds conform with the assumption that a significant amount of dark matter is located in the invisible outer parts of the extended halos, sufficient to fill the gap between the observed and expected local matter density. Nearby groups of galaxies and the Virgo cluster have dark halos which seem to extend up to their zero-gravity surfaces. If the extended halo is a common feature of gravitationally bound systems on scales of galaxy groups and clusters, the Local Universe could be typical or even

  15. Dark matter dynamics and indirect detection

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, Gianfranco; /Fermilab; Merritt, David; /Rochester Inst. Tech.

    2005-04-01

    Non-baryonic, or ''dark'', matter is believed to be a major component of the total mass budget of the universe. We review the candidates for particle dark matter and discuss the prospects for direct detection (via interaction of dark matter particles with laboratory detectors) and indirect detection (via observations of the products of dark matter self-annihilations), focusing in particular on the Galactic center, which is among the most promising targets for indirect detection studies. The gravitational potential at the Galactic center is dominated by stars and by the supermassive black hole, and the dark matter distribution is expected to evolve on sub-parsec scales due to interaction with these components. We discuss the dominant interaction mechanisms and show how they can be used to rule out certain extreme models for the dark matter distribution, thus increasing the information that can be gleaned from indirect detection searches.

  16. Study of new germanium bolometers with interleaved concentric electrodes for non-baryonic cold dark matter direct detection in the Edelweiss-II experiment

    International Nuclear Information System (INIS)

    EDELWEISS is a direct non-baryonic cold dark matter detection experiment in the form of weakly interacting massive particles (also known as WIMPs), which currently constitute the most popular candidates to account for the missing mass in the Universe. To this purpose, EDELWEISS uses germanium bolometers at cryogenic temperature (20 mK approximately) in the Underground Laboratory of Modane (LSM) at the French-Italian border. Since 2008, a new type of detector is operated, equipped with concentric electrodes to optimize the rejection of surface events (coplanar-grid detectors). This thesis work is divided into several research orientations. First, we carried out measurements concerning charge collection in the crystals. The velocity laws of the carriers (electrons and holes) have been determined in germanium at 20 mK in the orientation, and a complete study of charge sharing has been done, including an evaluation of the transport anisotropy and of the straggling of the carriers. These results lead to a better understanding of the inner properties of the EDELWEISS detectors. Then, studies relating to the improvement of the performances were carried out. In particular, we have optimized the space-charge cancellation procedure in the crystals and improved the passive rejection of surface events (β). The fiducial volume of the detectors has been evaluated using two X-ray lines from cosmically activated radionuclides: 68Ge and 65Zn. Finally, an exhaustive study of the low energy spectra has been carried out, which makes it possible to develop a systematic analysis method for the search of low-mass WIMPs in EDELWEISS. (author)

  17. Atomic Dark Matter

    OpenAIRE

    Kaplan, David E.; Krnjaic, Gordan Z.; Rehermann, Keith R.; Wells, Christopher M.

    2009-01-01

    We propose that dark matter is dominantly comprised of atomic bound states. We build a simple model and map the parameter space that results in the early universe formation of hydrogen-like dark atoms. We find that atomic dark matter has interesting implications for cosmology as well as direct detection: Protohalo formation can be suppressed below $M_{proto} \\sim 10^3 - 10^6 M_{\\odot}$ for weak scale dark matter due to Ion-Radiation interactions in the dark sector. Moreover, weak-scale dark a...

  18. Dark Matter: A Primer

    OpenAIRE

    Katherine Garrett; Gintaras Dūda

    2010-01-01

    Dark matter is one of the greatest unsolved mysteries in cosmology at the present time. About 80% of the universe's gravitating matter is non-luminous, and its nature and distribution are for the most part unknown. In this paper, we will outline the history, astrophysical evidence, candidates, and detection methods of dark matter, with the goal to give the reader an accessible but rigorous introduction to the puzzle of dark matter. This review targets advanced students and researchers new to ...

  19. Gamma ray emission from a baryonic dark halo

    International Nuclear Information System (INIS)

    A re-analysis of EGRET data by Dixon et al has led to the discovery of a statistically significant diffuse γ-ray emission from the galactic halo. We show that this emission can naturally be accounted for within a previously proposed model for baryonic dark matter, according to which dark clusters of brown dwarfs and cold self-gravitating H2 clouds populate the outer galactic halo and can show up in microlensing observations. Basically, cosmic-ray protons in the galactic halo scatter on the clouds clumped into dark clusters, giving rise to the observed γ-ray flux. We derive maps for the corresponding intensity distribution, which turn out to be in remarkably good agreement with those obtained by Dixon et al. We also address future prospects to test our predictions

  20. Gamma ray emission from a baryonic dark halo

    Energy Technology Data Exchange (ETDEWEB)

    De Paolis, F.; Ingrosso, G. [Dipartimento di Fisica, Universita di Lecce and INFN, Sezione di Lecce, CP 193, I-73100 Lecce (Italy); Jetzer, P.H. [Paul Scherrer Institute, Laboratory for Astrophysics, CH-5232 Villigen PSI, and Institute of Theoretical Physics, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland). E-mail: jetzer at iftp.unizh.ch; Roncadelli, M. [INFN, Sezione di Pavia, Via Bassi 6, I-27100 Pavia (Italy)

    2000-07-01

    A re-analysis of EGRET data by Dixon et al has led to the discovery of a statistically significant diffuse {gamma}-ray emission from the galactic halo. We show that this emission can naturally be accounted for within a previously proposed model for baryonic dark matter, according to which dark clusters of brown dwarfs and cold self-gravitating H{sub 2} clouds populate the outer galactic halo and can show up in microlensing observations. Basically, cosmic-ray protons in the galactic halo scatter on the clouds clumped into dark clusters, giving rise to the observed {gamma}-ray flux. We derive maps for the corresponding intensity distribution, which turn out to be in remarkably good agreement with those obtained by Dixon et al. We also address future prospects to test our predictions. (author)

  1. Gamma ray emission from a baryonic dark halo

    International Nuclear Information System (INIS)

    A re-analysis of EGRET data by Dixon et al has led to the discovery of a statistically significant diffuse γ-ray emission from the galactic halo. We show that this emission can naturally be accounted for within a previously proposed model for baryonic dark matter, according to which dark clusters of brown dwarfs and cold self-gravitating H2 clouds populate the outer galactic halo and can show up in microlensing observations. Basically, cosmic-ray protons in the galactic halo scatter on the clouds clumped into dark clusters, giving rise to the observed γ-ray flux. We derive maps for the corresponding intensity distribution, which turn out to be in remarkably good agreement with those obtained by Dixon et al. We also address future prospects to test our predictions. (author)

  2. Axino LSP baryogenesis and dark matter

    International Nuclear Information System (INIS)

    We discuss a new mechanism for baryogenesis, in which the baryon asymmetry is generated by the lightest supersymmetric particle (LSP) decay via baryonic R-parity-violating interactions. As a specific example, we use a supersymmetric axion model with an axino LSP. This scenario predicts large R-parity violation for the stop, and an upper limit on the squark masses between 15 and 130 TeV, for different choices of the Peccei-Quinn scale and the soft Xt terms. We discuss the implications for the nature of dark matter in light of the axino baryogenesis mechanism, and find that both the axion and a metastable gravitino can provide the correct dark matter density. In the axion dark matter scenario, the initial misalignment angle is restricted to be O(1). On the other hand, the reheating temperature is linked to the PQ scale and should be higher than 104–105 GeV in the gravitino dark matter scenario

  3. On the capture of dark matter by neutron stars

    OpenAIRE

    Güver, Tolga; Erkoca, Arif Emre; Reno, Mary Hall; Sarcevic, Ina

    2012-01-01

    We calculate the number of dark matter particles that a neutron star accumulates over its lifetime as it rotates around the center of a galaxy, when the dark matter particle is a self-interacting boson but does not self-annihilate. We take into account dark matter interactions with baryonic matter and the time evolution of the dark matter sphere as it collapses within the neutron star. We show that dark matter self-interactions play an important role in the rapid accumulation of dark matter i...

  4. Baryons and baryonic matter in four-fermion interaction models

    International Nuclear Information System (INIS)

    In this work we discuss baryons and baryonic matter in simple four-fermion interaction theories, the Gross-Neveu model and the Nambu-Jona-Lasinio model in 1+1 and 2+1 space-time dimensions. These models are designed as toy models for dynamical symmetry breaking in strong interaction physics. Pointlike interactions (''four-fermion'' interactions) between quarks replace the full gluon mediated interaction of quantum chromodynamics. We consider the limit of a large number of fermion flavors, where a mean field approach becomes exact. This method is formulated in the language of relativistic many particle theory and is equivalent to the Hartree-Fock approximation. In 1+1 dimensions, we generalize known results on the ground state to the case where chiral symmetry is broken explicitly by a bare mass term. For the Gross-Neveu model, we derive an exact self-consistent solution for the finite density ground state, consisting of a one-dimensional array of equally spaced potential wells, a baryon crystal. For the Nambu- Jona-Lasinio model we apply the derivative expansion technique to calculate the total energy in powers of derivatives of the mean field. In a picture akin to the Skyrme model of nuclear physics, the baryon emerges as a topological soliton. The solution for both the single baryon and dense baryonic matter is given in a systematic expansion in powers of the pion mass. The solution of the Hartree-Fock problem is more complicated in 2+1 dimensions. In the massless Gross-Neveu model we derive an exact self-consistent solution by extending the baryon crystal of the 1+1 dimensional model, maintaining translational invariance in one spatial direction. This one-dimensional configuration is energetically degenerate to the translationally invariant solution, a hint in favor of a possible translational symmetry breakdown by more general geometrical structures. In the Nambu-Jona-Lasinio model, topological soliton configurations induce a finite baryon number. In contrast

  5. Asymmetric dark matter and the Sun

    DEFF Research Database (Denmark)

    Frandsen, Mads Toudal; Sarkar, Subir

    2010-01-01

    Cold dark matter particles with an intrinsic matter-antimatter asymmetry do not annihilate after gravitational capture by the Sun and can affect its interior structure. The rate of capture is exponentially enhanced when such particles have self-interactions of the right order to explain structure...... formation on galactic scales. A `dark baryon' of mass 5 GeV is a natural candidate and has the required relic abundance if its asymmetry is similar to that of ordinary baryons. We show that such particles can solve the `solar composition problem'. The predicted small decrease in the low energy neutrino...

  6. Dark matter and IceCube neutrinos

    CERN Document Server

    Biondi, Riccardo

    2015-01-01

    We show that the excess of high energy neutrinos observed by the IceCube collaboration at energies above 100 TeV might originate from baryon number violating decays of heavy shadow baryons from mirror sector, which in turn constitute Dark Matter. Due to tiny mixing between mirror and ordinary neutrinos, it is possible to explain the specific features of the IceCube events spectrum.

  7. Dissipative dark matter explains rotation curves

    CERN Document Server

    Foot, R

    2015-01-01

    Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken $U(1)'$ gauge symmetry, leading to a dark photon. Previous work has shown that such models can not only explain the LSS and CMB, but potentially also dark matter phenomena on small scales, such as the inferred cored structure of dark matter halos. In this picture, dark matter halos of disk galaxies not only cool via dissipative interactions but are also heated via ordinary supernovae (facilitated by an assumed photon - dark photon kinetic mixing interaction). This interaction between the dark matter halo and ordinary baryons, a very special feature of these types of models, plays a critical role in governing the physical properties of the dark matter halo. Here, we further study the implications of this type of dissipative dark matter for disk galaxies. Building on earlier work, we develop a simpl...

  8. Neutrinos and dark matter

    International Nuclear Information System (INIS)

    Neutrinos could be key particles to unravel the nature of the dark matter of the Universe. On the one hand, sterile neutrinos in minimal extensions of the Standard Model are excellent dark matter candidates, producing potentially observable signals in the form of a line in the X-ray sky. On the other hand, the annihilation or the decay of dark matter particles produces, in many plausible dark matter scenarios, a neutrino flux that could be detected at neutrino telescopes, thus providing non-gravitational evidence for dark matter. More conservatively, the non-observation of a significant excess in the neutrino fluxes with respect to the expected astrophysical backgrounds can be used to constrain dark matter properties, such as the self-annihilation cross section, the scattering cross section with nucleons and the lifetime

  9. Neutrinos and dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Ibarra, Alejandro [Physik-Department T30d, Technische Universität München, James-Franck-Straße, 85748 Garching (Germany)

    2015-07-15

    Neutrinos could be key particles to unravel the nature of the dark matter of the Universe. On the one hand, sterile neutrinos in minimal extensions of the Standard Model are excellent dark matter candidates, producing potentially observable signals in the form of a line in the X-ray sky. On the other hand, the annihilation or the decay of dark matter particles produces, in many plausible dark matter scenarios, a neutrino flux that could be detected at neutrino telescopes, thus providing non-gravitational evidence for dark matter. More conservatively, the non-observation of a significant excess in the neutrino fluxes with respect to the expected astrophysical backgrounds can be used to constrain dark matter properties, such as the self-annihilation cross section, the scattering cross section with nucleons and the lifetime.

  10. Axions and Dark Matter

    OpenAIRE

    Yang, Qiaoli

    2015-01-01

    Dark matter particles constitute $23\\%$ of the total energy density of our universe and their exact properties are still unclear besides that they must be very cold and weakly interacting with the standard model particles. Many beyond standard model theories provide proper candidates to serve as the dark matter. The axions were introduced to solve the strong CP problem and later turned out to be a very attractive dark matter candidate. In this paper, we briefly review the physics of axions an...

  11. Dark matter 2013

    International Nuclear Information System (INIS)

    This article reviews the status of the exciting and fastly evolving field of dark matter research as of summer 2013, when it was discussed at the International Cosmic Ray Conference (ICRC) 2013 in Rio de Janeiro. It focuses on the three main avenues to detect weakly interacting massive particle (WIMP) dark matter: direct detection, indirect detection, and collider searches. The article is based on the dark matter rapporteur talk summarizing the presentations given at the conference, filling some gaps for completeness. (author)

  12. Clumpy cold dark matter

    Science.gov (United States)

    Silk, Joseph; Stebbins, Albert

    1993-01-01

    A study is conducted of cold dark matter (CDM) models in which clumpiness will inhere, using cosmic strings and textures suited to galaxy formation. CDM clumps of 10 million solar mass/cu pc density are generated at about z(eq) redshift, with a sizable fraction surviving. Observable implications encompass dark matter cores in globular clusters and in galactic nuclei. Results from terrestrial dark matter detection experiments may be affected by clumpiness in the Galactic halo.

  13. Hidden Dipole Dark Matter

    CERN Document Server

    Pierce, Aaron

    2014-01-01

    We consider models where a hidden U(1)' interacts with the Standard Model via kinetic mixing. We assume the dark matter is neutral under this U(1)', but interacts with it via higher dimension operators. In particular, we consider a hidden dipole operator for fermionic dark matter, and charge radius and Rayleigh operators for scalar dark matter. These models naturally explain the absence of direct detection signals, but allow for a thermal cosmology. LHC searches for the Z' represent a powerful probe.

  14. Originally Asymmetric Dark Matter

    CERN Document Server

    Okada, Nobuchika

    2012-01-01

    We propose a scenario with a fermion dark matter, where the dark matter particle used to be the Dirac fermion, but it takes the form of the Majorana fermion at a late time. The relic number density of the dark matter is determined by the dark matter asymmetry generated through the same mechanism as leptogenesis when the dark matter was the Dirac fermion. After efficient dark matter annihilation processes have frozen out, a phase transition of a scalar field takes place and generates Majorana mass terms to turn the dark matter particle into the Majorana fermion. In order to address this scenario in detail, we propose two simple models. The first one is based on the Standard Model (SM) gauge group and the dark matter originates the $SU(2)_L$ doublet Dirac fermion, analogous to the Higgsino-like neutralino in supersymmetric models. We estimate the spin-independent/dependent elastic scattering cross sections of this late-time Majorana dark matter with a proton and find the possibility to discover it by the direct...

  15. A new method to quantify the effects of baryons on the matter power spectrum

    CERN Document Server

    Schneider, Aurel

    2015-01-01

    Future large-scale galaxy surveys have the potential to become leading probes for cosmology provided the influence of baryons on the total mass distribution is understood well enough. As hydrodynamical simulations strongly depend on details in the feedback implementations, no unique and robust predictions for baryonic effects currently exist. In this paper we propose a baryonic correction model that modifies the density field of dark-matter-only $N$-body simulations to mimic the effects of baryons from any underlying adopted feedback recipe. The model assumes haloes to consist of 4 components: 1- hot gas in hydrostatical equilibrium, 2- ejected gas from feedback processes, 3- central galaxy stars, and 4- adiabatically relaxed dark matter, which all modify the initial dark-matter-only density profiles. This altered mass profiles allow to define a displacement field for particles in $N$-body simulations and to modify the total density field accordingly. The main advantage of the baryonic correction model is to ...

  16. Course 6. dark matter: direct detection

    International Nuclear Information System (INIS)

    Determining the precise nature of dark matter is one of the main open questions of contemporary physics. The search for non-baryonic dark matter is strongly motivated by present data and 3 particle candidates: wimps (weakly interactive massive particles), axions and massive neutrinos are actively searched by several experiments (GENIUS, HDMS, CDMS, EDELWEISS, LLNL, CARRACK, SOLAX, DAMA,...). In this course the author reviews and summarizes the experimental situation and analyzes the main detection strategies developed to identify the dark matter candidates. (A.C.)

  17. Dark Matter from new Technicolor Theories

    DEFF Research Database (Denmark)

    Bjarke Gudnason, Sven; Kouvaris, Christoforos; Sannino, Francesco

    2006-01-01

    We investigate dark matter candidates emerging in recently proposed technicolor theories. We determine the relic density of the lightest, neutral, stable technibaryon having imposed weak thermal equilibrium conditions and overall electric neutrality of the Universe. In addition we consider...... sphaleron processes that violate baryon, lepton and technibaryon number. Our analysis is performed in the case of a first order electroweak phase transition as well as a second order one. We argue that, in both cases, the new technibaryon contributes to the dark matter in the Universe. Finally we examine...... the problem of the constraints on these types of dark matter components from earth based experiments....

  18. Dipolar Dark Matter

    CERN Document Server

    Blanchet, Luc

    2015-01-01

    Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because the two types of dark matter interact through the vector field, a ghostly degree of fre...

  19. Perfect fluid dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Rahaman, F., E-mail: farook_rahaman@yahoo.co [Department of Mathematics, Jadavpur University, Kolkata 700 032, West Bengal (India); Nandi, K.K., E-mail: kamalnandi1952@yahoo.co.i [Department of Mathematics, North Bengal University, Siliguri 734013, West Bengal (India); Bhadra, A., E-mail: aru_bhadra@yahoo.co [High Energy and Cosmic Ray Research Centre, University of North Bengal, Siliguri, WB 734013 (India); Kalam, M., E-mail: mehedikalam@yahoo.co.i [Department of Physics, Netaji Nagar College for Women, Regent Estate, Kolkata 700092 (India); Chakraborty, K., E-mail: kchakraborty28@yahoo.co [Department of Physics, Government Training College, Hooghly 712103, West Bengal (India)

    2010-10-25

    Taking the flat rotation curve as input and treating the matter content in the galactic halo region as perfect fluid we obtain a space-time metric at the galactic halo region in the framework of general relativity. We find that the resultant space-time metric is a non-relativistic dark matter induced space-time embedded in a static Friedmann-Lemaitre-Robertson-Walker universe i.e. the flat rotation curve not only leads to the existence of dark matter but also suggests about the background geometry of the universe. Within its range of validity the flat rotation curve and the demand that the dark matter to be non-exotic together indicate for a (nearly) flat universe as favored by the modern cosmological observations. We obtain the expressions for energy density and pressure of dark matter there and consequently the equation of state of dark matter. Various other aspects of the solutions are also analyzed.

  20. Perfect fluid dark matter

    International Nuclear Information System (INIS)

    Taking the flat rotation curve as input and treating the matter content in the galactic halo region as perfect fluid we obtain a space-time metric at the galactic halo region in the framework of general relativity. We find that the resultant space-time metric is a non-relativistic dark matter induced space-time embedded in a static Friedmann-Lemaitre-Robertson-Walker universe i.e. the flat rotation curve not only leads to the existence of dark matter but also suggests about the background geometry of the universe. Within its range of validity the flat rotation curve and the demand that the dark matter to be non-exotic together indicate for a (nearly) flat universe as favored by the modern cosmological observations. We obtain the expressions for energy density and pressure of dark matter there and consequently the equation of state of dark matter. Various other aspects of the solutions are also analyzed.

  1. Dark Matter Detection in Space

    OpenAIRE

    Feng, Jonathan L.

    2004-01-01

    I review prospects for detecting dark matter in space-based experiments, with an emphasis on recent developments. I propose the ``Martha Stewart criterion'' for identifying dark matter candidates that are particularly worth investigation and focus on three that satisfy it: neutralino dark matter, Kaluza-Klein dark matter, and superWIMP gravitino dark matter.

  2. Signals of Particle Dark Matter

    OpenAIRE

    Lin, Tongyan

    2012-01-01

    This thesis explores methods of detecting dark matter particles, with some emphasis on several dark matter models of current interest. Detection in this context means observation of an experimental signature correlated with dark matter interactions with Standard Model particles. This includes recoils of nuclei or electrons from dark matter scattering events, and direct or indirect observation of particles produced by dark matter annihilation.

  3. Nonthermal production of dark radiation and dark matter

    CERN Document Server

    Reece, Matthew

    2015-01-01

    Dark matter may be coupled to dark radiation: light degrees of freedom that mediate forces between dark sector particles. Cosmological constraints favor dark radiation that is colder than Standard Model radiation. In models with fixed couplings between dark matter and the Standard Model, these constraints can be difficult to satisfy if thermal equilibrium is assumed in the early universe. We construct a model of asymmetric reheating of the visible and dark sectors from late decays of a long-lived particle (for instance, a modulus). We show, as a proof-of-principle, that such a model can populate a sufficiently cold dark sector while also generating baryon and dark matter asymmetries through the out of equilibrium decay. We frame much of our discussion in terms of the scenario of dissipative dark matter, as in the Double-Disk Dark Matter scenario. However, our results may also be of interest for other scenarios like the Twin Higgs model that are in danger of overproducing dark radiation due to nonnegligible da...

  4. Thermal Relic Dark Matter Beyond the Unitarity Limit

    CERN Document Server

    Harigaya, Keisuke; Kaneta, Kunio; Nakano, Wakutaka; Suzuki, Motoo

    2016-01-01

    We discuss a simple model of thermal relic dark matter whose mass can be much larger than the so-called unitarity limit on the mass of point-like particle dark matter. The model consists of new strong dynamics with one flavor of fermions in the fundamental representation which is much heavier than the dynamical scale of the new strong dynamics. Dark matter is identified with the lightest baryonic hadron of the new dynamics. The baryonic hadrons annihilate into the mesonic hadrons of the new strong dynamics when they have large radii. Resultantly, thermal relic dark matter with a mass in the PeV range is possible.

  5. A Dark Matter Candidate with New Strong Interactions

    OpenAIRE

    Banks, T.; Mason, J. D.; O'Neil, D.

    2005-01-01

    We study the possibility that dark matter is a baryon of a new strongly interacting gauge theory, which was introduced in the low energy theory of Cosmological SUSY Breaking (CSB). This particle can fit the observed dark matter density if an appropriate cosmological asymmetry is generated. The same mechanism can also explain the dark/baryonic matter ratio in the universe. The mass of the dark matter particle is in the multiple TeV range, and could be as high as 20 TeV.

  6. Singlet fermion dark matter within left-right model

    OpenAIRE

    Sudhanwa Patra; Soumya Rao

    2016-01-01

    We discuss singlet fermion dark matter within a left-right symmetric model promoting baryon and lepton numbers as separate gauge symmetries. We add a simple Dirac fermionic dark matter singlet under SU(2)L,R with nonzero and equal baryon and lepton number which ensures electric charge neutrality. Such a dark matter candidate interacts with SM particles through the extra ZB,ℓ gauge bosons. This can give rise to a dark matter particle of a few hundred GeV that couples to ∼TeV scale gauge bosons...

  7. Analysis of dark matter and dark energy

    Science.gov (United States)

    Yongquan, Han

    2016-05-01

    As the law of unity of opposites of the Philosophy tells us, the bright material exists, the dark matter also exists. Dark matter and dark energy should allow the law of unity of opposites. The Common attributes of the matter is radiation, then common attributes of dark matter must be absorb radiation. Only the rotation speed is lower than the speed of light radiation, can the matter radiate, since the speed of the matter is lower than the speed of light, so the matter is radiate; The rotate speed of the dark matter is faster than the light , so the dark matter doesn't radiate, it absorbs radiation. The energy that the dark matter absorb radiation produced (affect the measurement of time and space distribution of variations) is dark energy, so the dark matter produce dark energy only when it absorbs radiation. Dark matter does not radiate, two dark matters does not exist inevitably forces, and also no dark energy. Called the space-time ripples, the gravitational wave is bent radiation, radiation particles should be graviton, graviton is mainly refers to the radiation particles whose wavelength is small. Dark matter, dark energy also confirms the existence of the law of symmetry.

  8. Twin Higgs Asymmetric Dark Matter

    CERN Document Server

    García, Isabel García; March-Russell, John

    2015-01-01

    We study Asymmetric Dark Matter (ADM) in the context of the minimal (Fraternal) Twin Higgs solution to the little hierarchy problem, with a twin sector with gauged $SU(3)' \\times SU(2)'$, a twin Higgs, and only third generation twin fermions. Naturalness requires the QCD$^\\prime$ scale $\\Lambda'_{\\rm QCD} \\simeq 0.5 - 20 \\ {\\rm GeV}$, and $t'$ to be heavy. We focus on the light $b'$ quark regime, $m_{b'} \\lesssim \\Lambda'_{\\rm QCD}$, where QCD$^\\prime$ is characterised by a single scale $\\Lambda'_{\\rm QCD}$ with no light pions. A twin baryon number asymmetry leads to a successful DM candidate: the spin-3/2 twin baryon, $\\Delta' \\sim b'b'b'$, with a dynamically determined mass ($\\sim 5 \\Lambda'_{\\rm QCD}$) in the preferred range for the DM-to-baryon ratio $\\Omega_{\\rm DM}/\\Omega_{\\rm baryon} \\simeq 5$. Gauging the $U(1)'$ group leads to twin atoms ($\\Delta'$ - $\\bar {\\tau'}$ bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo ...

  9. Asymptotically Safe Dark Matter

    DEFF Research Database (Denmark)

    Sannino, Francesco; Shoemaker, Ian M.

    2015-01-01

    We introduce a new paradigm for dark matter (DM) interactions in which the interaction strength is asymptotically safe. In models of this type, the coupling strength is small at low energies but increases at higher energies, and asymptotically approaches a finite constant value. The resulting...... searches are the primary ways to constrain or discover asymptotically safe dark matter....

  10. Hidden Charged Dark Matter

    CERN Document Server

    Feng, Jonathan L; Tu, Huitzu; Yu, Hai-Bo

    2009-01-01

    We examine the possibility that dark matter is hidden, that is, neutral under all standard model gauge interactions, but charged under an exact U(1) gauge symmetry of the hidden sector. Such candidates are predicted in simple WIMPless models, supersymmetric models in which hidden dark matter has the desired thermal relic density for a wide range of masses. Hidden charged dark matter has many potentially disastrous implications for astrophysics: (1) bound state formation and Sommerfeld-enhanced annihilation after chemical freeze out may destroy its relic density, (2) similar effects greatly enhance dark matter annihilation in protohalos at redshifts of z ~ 30, (3) Compton scattering off hidden photons delays kinetic decoupling, suppressing small scale structure, and (4) Rutherford scattering makes such dark matter self-interacting and collisional, potentially violating constraints from the Bullet Cluster and the observed morphology of galactic halos. We show that all of these constraints are satisfied and are ...

  11. Dark matter response to galaxy formation

    CERN Document Server

    Tissera, Patricia B; Pedrosa, Susana; Scannapieco, Cecilia

    2009-01-01

    We have resimulated the six galaxy-sized haloes of the Aquarius Project including metal-dependent cooling, star formation and supernova feedback. This allows us to study not only how dark matter haloes respond to galaxy formation, but also how this response is affected by details of halo assembly history. In agreement with previous work, we find baryon condensation to lead to increased dark matter concentration. Dark matter density profiles differ substantially in shape from halo to halo when baryons are included, but in all cases the velocity dispersion decreases monotonically with radius. Some haloes show an approximately constant dark matter velocity anisotropy with $ \\beta \\approx 0.1-02$, while others retain the anisotropy structure of their baryon-free versions. Most of our haloes become approximately oblate in their inner regions, although a few retain the shape of their dissipationless counterparts. Pseudo-phase-space densities are described by a power law in radius of altered slope when baryons are i...

  12. GUTzilla Dark Matter

    OpenAIRE

    Harigaya, Keisuke; Lin, Tongyan; Lou, Hou Keong

    2016-01-01

    Motivated by gauge coupling unification and dark matter, we present an extension to the Standard Model where both are achieved by adding an extra new matter multiplet. Such considerations lead to a Grand Unified Theory with very heavy WIMPzilla dark matter, which has mass greater than ~10^7 GeV and must be produced before reheating ends. Naturally, we refer to this scenario as GUTzilla dark matter. Here we present a minimal GUTzilla model, adding a vector-like quark multiplet to the Standard ...

  13. Composite Millicharged Dark Matter

    CERN Document Server

    Kouvaris, Chris

    2013-01-01

    We study a composite millicharged dark matter model. The dark matter is in the form of pion-like objects emerging from a higher scale QCD-like theory. We present two distinct possibilities with interesting phenomenological consequences based on the choice of the parameters. In the first one, the dark matter is produced non-thermally and it could potentially account for the 130 GeV Fermi photon line via decays of the "dark pions". We estimate the self-interaction cross section which might play an important role both in changing the dark matter halo profile at the center of the galaxy and in making the dark matter warmer. In the second version the dark matter is produced via the freeze-in mechanism. Finally we impose all possible astrophysical, cosmological and experimental constraints. We study in detail generic constraints on millicharged dark matter that can arise from anomalous isotope searches of different elements and we show why constraints based on direct searches from underground detectors are not gene...

  14. Composite millicharged dark matter

    Science.gov (United States)

    Kouvaris, Chris

    2013-07-01

    We study a composite millicharged dark matter model. The dark matter is in the form of pionlike objects emerging from a higher scale QCD-like theory. We present two distinct possibilities with interesting phenomenological consequences based on the choice of the parameters. In the first one, the dark matter is produced nonthermally, and it could potentially account for the 130 GeV Fermi photon line via decays of the “dark pions.” We estimate the self-interaction cross section, which might play an important role both in changing the dark matter halo profile at the center of the galaxy and in making the dark matter warmer. In the second version the dark matter is produced via the freeze-in mechanism. Finally we impose all possible astrophysical, cosmological and experimental constraints. We study in detail generic constraints on millicharged dark matter that can arise from anomalous isotope searches of different elements and we show why constraints based on direct searches from underground detectors are not generally valid.

  15. Missing dark matter in dwarf galaxies?

    Science.gov (United States)

    Oman, Kyle A.; Navarro, Julio F.; Sales, Laura V.; Fattahi, Azadeh; Frenk, Carlos S.; Sawala, Till; Schaller, Matthieu; White, Simon D. M.

    2016-08-01

    We use cosmological hydrodynamical simulations of the APOSTLE project to examine the fraction of baryons in $\\Lambda$CDM haloes that collect into galaxies. This `galaxy formation efficiency' correlates strongly and with little scatter with halo mass, dropping steadily towards dwarf galaxies. The baryonic mass of a galaxy may thus be used to place a lower limit on total halo mass and, consequently, on its asymptotic maximum circular velocity. A number of dwarfs seem to violate this constraint, having baryonic masses up to ten times higher than expected from their rotation speeds, or, alternatively, rotating at only half the speed expected for their mass. Taking the data at face value, either these systems have formed galaxies with extraordinary efficiency - highly unlikely given their shallow potential wells - or they inhabit haloes with extreme deficits in their dark matter content. This `missing dark matter' is reminiscent of the inner mass deficits of galaxies with slowly-rising rotation curves, but extends to regions larger than the luminous galaxies themselves, disfavouring explanations based on star formation-induced `cores' in the dark matter. An alternative could be that galaxy inclination errors have been underestimated, and that these are just systems where inferred mass profiles have been compromised by systematic uncertainties in interpreting the velocity field. This should be investigated further, since it might provide a simple explanation not only for missing-dark-matter galaxies but also for other challenges to our understanding of the inner structure of cold dark matter haloes.

  16. Constraints on the Coupling between Dark Energy and Dark Matter from CMB data

    OpenAIRE

    Murgia, Riccardo; Gariazzo, Stefano; Fornengo, Nicolao

    2016-01-01

    We investigate a phenomenological non-gravitational coupling between dark energy and dark matter, where the interaction in the dark sector is parameterized as an energy transfer either from dark matter to dark energy or the opposite. The models are constrained by a whole host of updated cosmological data: cosmic microwave background temperature anisotropies and polarization, high-redshift supernovae, baryon acoustic oscillations, redshift space distortions and gravitational lensing. Both mode...

  17. Asymmetric Dark Matter from Leptogenesis

    OpenAIRE

    Falkowski, Adam; Ruderman, Joshua T.; Volansky, Tomer

    2011-01-01

    We present a new realization of asymmetric dark matter in which the dark matter and lepton asymmetries are generated simultaneously through two-sector leptogenesis. The right-handed neutrinos couple both to the Standard Model and to a hidden sector where the dark matter resides. This framework explains the lepton asymmetry, dark matter abundance and neutrino masses all at once. In contrast to previous realizations of asymmetric dark matter, the model allows for a wide range of dark matter mas...

  18. Missing dark matter in dwarf galaxies?

    CERN Document Server

    Oman, Kyle A; Sales, Laura V; Fattahi, Azadeh; Frenk, Carlos S; Sawala, Till; Schaller, Matthieu; White, Simon D M

    2016-01-01

    We use cosmological hydrodynamical simulations of the APOSTLE project to examine the fraction of baryons in $\\Lambda$CDM haloes that collect into galaxies. This `galaxy formation efficiency' correlates strongly and with little scatter with halo mass, dropping steadily towards dwarf galaxies. The baryonic mass of a galaxy may thus be used to place a lower limit on total halo mass and, consequently, on its asymptotic maximum circular velocity. A number of dwarfs seem to violate this constraint, having baryonic masses up to ten times higher than expected from their rotation speeds, or, alternatively, rotating at only half the speed expected for their mass. Taking the data at face value, either these systems have formed galaxies with extraordinary efficiency - highly unlikely given their shallow potential wells - or they inhabit haloes with extreme deficits in their dark matter content. This `missing dark matter' is reminiscent of the inner mass deficits of galaxies with slowly-rising rotation curves, but extends...

  19. Exothermic Dark Matter

    CERN Document Server

    Graham, Peter W; Rajendran, Surjeet; Saraswat, Prashant

    2010-01-01

    We propose a novel mechanism for dark matter to explain the observed annual modulation signal at DAMA/LIBRA which avoids existing constraints from every other dark matter direct detection experiment including CRESST, CDMS, and XENON10. The dark matter consists of at least two light states with mass ~few GeV and splittings ~5 keV. It is natural for the heavier states to be cosmologically long-lived and to make up an O(1) fraction of the dark matter. Direct detection rates are dominated by the exothermic reactions in which an excited dark matter state down-scatters off of a nucleus, becoming a lower energy state. In contrast to (endothermic) inelastic dark matter, the most sensitive experiments for exothermic dark matter are those with light nuclei and low threshold energies. Interestingly, this model can also naturally account for the observed low-energy events at CoGeNT. The only significant constraint on the model arises from the DAMA/LIBRA unmodulated spectrum but it can be tested in the near future by a lo...

  20. Dissipative dark matter and the rotation curves of dwarf galaxies

    CERN Document Server

    Foot, R

    2015-01-01

    There is ample evidence from rotation curves that dark matter halo's around disk galaxies have nontrivial dynamics. Of particular significance are: a) the cored dark matter profile of disk galaxies, b) correlations of the shape of rotation curves with baryonic properties, and c) the Tully-Fisher relation. Dark matter halo's around disk galaxies may have nontrivial dynamics if dark matter is strongly self interacting and dissipative. Multicomponent hidden sector dark matter featuring a massless `dark photon' (from an unbroken dark $U(1)$ gauge interaction) which kinetically mixes with the ordinary photon provides a concrete example of such dark matter. The kinetic mixing interaction facilitates halo heating by enabling ordinary supernovae to be a source of these `dark photons'. Dark matter halo's can expand and contract in response to the heating and cooling processes, but for a sufficiently isolated halo should have evolved to a steady state or `equilibrium' configuration where heating and cooling rates local...

  1. Cosmology: Dark matter and dark energy

    OpenAIRE

    Caldwell, Robert; Kamionkowski, Marc

    2009-01-01

    Observations continue to indicate that the Universe is dominated by invisible components — dark matter and dark energy. Shedding light on this cosmic darkness is a priority for astronomers and physicists.

  2. Dark matter searches

    CERN Document Server

    Baudis, Laura

    2015-01-01

    One of the major challenges of modern physics is to decipher the nature of dark matter. Astrophysical observations provide ample evidence for the existence of an invisible and dominant mass component in the observable universe, from the scales of galaxies up to the largest cosmological scales. The dark matter could be made of new, yet undiscovered elementary particles, with allowed masses and interaction strengths with normal matter spanning an enormous range. Axions, produced non-thermally in the early universe, and weakly interacting massive particles (WIMPs), which froze out of thermal equilibrium with a relic density matching the observations, represent two well-motivated, generic classes of dark matter candidates. Dark matter axions could be detected by exploiting their predicted coupling to two photons, where the highest sensitivity is reached by experiments using a microwave cavity permeated by a strong magnetic field. WIMPs could be directly observed via scatters off atomic nuclei in underground, ultr...

  3. The dark matter distribution of M87 and NGC 1399

    Science.gov (United States)

    Tsai, John C.

    1993-01-01

    Recent X-ray observations of clusters of galaxies indicate that, outside the innermost about 100 kpc region, the ratio of dark matter density to baryonic matter density declines with radius. We show that this result is consistent with a cold dark matter simulation, suggesting the presence of dissipationless dark matter in the observed clusters. This is contrary to previous suggestions that dissipational baryonic dark matter is required to explain the decline in the density ratio. The simulation further shows that, in the inner 100 kpc region, the density ratio should rise with radius. We confirm this property in M87 and NGC 1399, which are close enough to allow the determination of the density ratio in the required inner region. X-ray mappings of the dark matter distribution in clusters of galaxies are therefore consistent with the presence of dissipationless dark matter.

  4. Dark Matter 2014

    CERN Document Server

    Schumann, Marc

    2015-01-01

    This article gives an overview on the status of experimental searches for dark matter at the end of 2014. The main focus is on direct searches for weakly interacting massive particles (WIMPs) using underground-based low-background detectors, especially on the new results published in 2014. WIMPs are excellent dark matter candidates, predicted by many theories beyond the standard model of particle physics, and are expected to interact with the target nuclei either via spin-independent (scalar) or spin-dependent (axial-vector) couplings. Non-WIMP dark matter candidates, especially axions and axion-like particles are also briefly discussed.

  5. Dark Matter in ATLAS

    CERN Document Server

    Resconi, Silvia; The ATLAS collaboration

    2016-01-01

    Results of Dark Matter searches in mono-X analysis with the ATLAS experiment at the Large Hadron Collider are reported. The data were collected in proton–proton collisions at a centre-of-mass energy of 13 TeV and correspond to an integrated luminosity of 3.2 fb-1. A description of the main characteristics of each analysis and how the main backgrounds are estimated is shown. The observed data are in agreement with the expected Standard Model backgrounds for all analysis described. Exclusion limits are presented for Dark Matter models including pair production of dark matter candidates.

  6. Dark Matter in ATLAS

    CERN Document Server

    Resconi, Silvia; The ATLAS collaboration

    2016-01-01

    An overview of Dark Matter searches with the ATLAS experiment at the Large Hadron Collider (LHC) is shown. Results of Mono-X analyses requiring large missing transverse momentum and a recoiling detectable physics object (X) are reported. The data were collected in proton-proton collisions at a centre-of-mass energy of 13 TeV. The observed data are in agreement with the expected Standard Model backgrounds for all analyses described. Exclusion limits are presented for Dark Matter models including pair production of Dark Matter candidates.

  7. Cold Dark Matter from Dark Energy

    OpenAIRE

    Davidson, Aharon; Karasik, David; Lederer, Yoav

    2001-01-01

    Dark energy/matter unification is first demonstrated within the framework of a simplified model. Geodetic evolution of a cosmological constant dominated bubble Universe, free of genuine matter, is translated into a specific FRW cosmology whose effectively induced dark component highly resembles the cold dark matter ansatz. The realistic extension constitutes a dark soliton which bridges past (radiation and/or matter dominated) and future (cosmological constant dominated) Einstein regimes; its...

  8. Resonant SIMP dark matter

    Directory of Open Access Journals (Sweden)

    Soo-Min Choi

    2016-07-01

    Full Text Available We consider a resonant SIMP dark matter in models with two singlet complex scalar fields charged under a local dark U(1D. After the U(1D is broken down to a Z5 discrete subgroup, the lighter scalar field becomes a SIMP dark matter which has the enhanced 3→2 annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic mixing between the SM hypercharge and dark gauge bosons can be used to make SIMP dark matter in kinetic equilibrium with the SM during freeze-out.

  9. Resonant SIMP dark matter

    Science.gov (United States)

    Choi, Soo-Min; Lee, Hyun Min

    2016-07-01

    We consider a resonant SIMP dark matter in models with two singlet complex scalar fields charged under a local dark U(1)D. After the U(1)D is broken down to a Z5 discrete subgroup, the lighter scalar field becomes a SIMP dark matter which has the enhanced 3 → 2 annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic mixing between the SM hypercharge and dark gauge bosons can be used to make SIMP dark matter in kinetic equilibrium with the SM during freeze-out.

  10. Dark Matter Gravitational Interactions

    CERN Document Server

    Tucker, R W

    1998-01-01

    We argue that the conjectured dark mater in the Universe may be endowed with a new kind of gravitational charge that couples to a short range gravitational interaction mediated by a massive vector field. A model is constructed that assimilates this concept into ideas of current inflationary cosmology. The model is also consistent with the observed behaviour of galactic rotation curves according to Newtonian dynamics. The essential idea is that stars composed of ordinary (as opposed to dark matter) experience Newtonian forces due to the presence of an all pervading background of massive gravitationally charged cold dark matter. The novel gravitational interactions are predicted to have a significant influence on pre-inflationary cosmology. The precise details depend on the nature of a gravitational Proca interaction and the description of matter. A gravitational Proca field configuration that gives rise to attractive forces between dark matter charges of like polarity exhibits homogeneous isotropic eternal cos...

  11. Xenophobic Dark Matter

    CERN Document Server

    Feng, Jonathan L; Sanford, David

    2013-01-01

    We consider models of xenophobic dark matter, in which isospin-violating dark matter-nucleon interactions significantly degrade the response of xenon direct detection experiments. For models of near-maximal xenophobia, with neutron-to-proton coupling ratio $f_n / f_p \\approx -0.64$, and dark matter mass near 8 GeV, the regions of interest for CoGeNT and CDMS-Si and the region of interest identified by Collar and Fields in CDMS-Ge data can be brought into agreement. This model may be tested in future direct, indirect, and collider searches. Interestingly, because the natural isotope abundance of xenon implies that xenophobia has its limits, we find that this xenophobic model may be probed in the near future by xenon experiments. Near-future data from the LHC and Fermi-LAT may also provide interesting alternative probes of xenophobic dark matter.

  12. Xenophobic dark matter

    Science.gov (United States)

    Feng, Jonathan L.; Kumar, Jason; Sanford, David

    2013-07-01

    We consider models of xenophobic dark matter, in which isospin-violating dark matter-nucleon interactions significantly degrade the response of xenon direct detection experiments. For models of near-maximal xenophobia, with neutron-to-proton coupling ratio fn/fp≈-0.64, and dark matter mass near 8 GeV, the regions of interest for CoGeNT and CDMS-Si and the region of interest identified by Collar and Fields in CDMS-Ge data can be brought into agreement. This model may be tested in future direct, indirect, and collider searches. Interestingly, because the natural isotope abundance of xenon implies that xenophobia has its limits, we find that this xenophobic model may be probed in the near future by xenon experiments. Near-future data from the LHC and Fermi-LAT may also provide interesting alternative probes of xenophobic dark matter.

  13. Cleaning up dark matter

    CERN Multimedia

    Bignami, Giovanni Fabrizio

    2006-01-01

    "An experiment in Italy has found tantalizing but puzzling evidence for axions, one if the leading candidates for dark matter. The authors explain how a pair of spinning neutron stars should settle the issue once and for all." (3 pages)

  14. Scalar Field Dark Matter

    CERN Document Server

    Matos, T; Urena-Lopez, L A; Núñez, D

    2001-01-01

    This work is a review of the last results of research on the Scalar Field Dark Matter model of the Universe at cosmological and at galactic level. We present the complete solution to the scalar field cosmological scenario in which the dark matter is modeled by a scalar field $\\Phi$ with the scalar potential $V(\\Phi)=V_{0}(cosh {(\\lambda \\sqrt{\\kappa_{0}}\\Phi)}-1)$ and the dark energy is modeled by a scalar field $\\Psi$, endowed with the scalar potential $\\tilde{V}(\\Psi)= \\tilde{V_{0}}(\\sinh{(\\alpha \\sqrt{\\kappa_{0}}\\Psi)})^{\\beta}$, which together compose the 95% of the total matter energy in the Universe. The model presents successfully deals with the up to date cosmological observations, and is a good candidate to treat the dark matter problem at the galactic level.

  15. Inflatable Dark Matter.

    Science.gov (United States)

    Davoudiasl, Hooman; Hooper, Dan; McDermott, Samuel D

    2016-01-22

    We describe a general scenario, dubbed "inflatable dark matter," in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early Universe. The overproduction of dark matter that is predicted within many, otherwise, well-motivated models of new physics can be elegantly remedied within this context. Thermal relics that would, otherwise, be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the nonthermal abundance of grand unified theory or Planck scale axions can be brought to acceptable levels without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ∼MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the standard model. PMID:26849584

  16. Elastically Decoupling Dark Matter

    CERN Document Server

    Kuflik, Eric; Lorier, Nicolas Rey-Le; Tsai, Yu-Dai

    2015-01-01

    We present a novel dark matter candidate, an Elastically Decoupling Relic (ELDER), which is a cold thermal relic whose present abundance is determined by the cross-section of its elastic scattering on Standard Model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross-section with electrons, photons and/or neutrinos in the $10^{-3}-1$ fb range.

  17. Elastically Decoupling Dark Matter.

    Science.gov (United States)

    Kuflik, Eric; Perelstein, Maxim; Lorier, Nicolas Rey-Le; Tsai, Yu-Dai

    2016-06-01

    We present a novel dark matter candidate, an elastically decoupling relic, which is a cold thermal relic whose present abundance is determined by the cross section of its elastic scattering on standard model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross section with electrons, photons and/or neutrinos in the 10^{-3}-1  fb range. PMID:27314712

  18. Monodromy Dark Matter

    OpenAIRE

    Jaeckel, Joerg; Mehta, Viraf M.; Witkowski, Lukas T.

    2016-01-01

    Light pseudo-Goldstone bosons such as, e.g. axion-like particles, that are non-thermally produced via the misalignment mechanism are promising dark matter candidates. An important feature of pseudo-Goldstone bosons is their periodic potential, whose scale of periodicity controls all their couplings. As a consequence of the periodicity the maximal potential energy is limited and, hence, producing the observed dark matter density poses significant constraints on the allowed masses and couplings...

  19. Asymptotically Safe Dark Matter

    CERN Document Server

    Sannino, Francesco

    2014-01-01

    We introduce a new paradigm for dark matter interactions according to which the interaction strength is asymptotically safe. In models of this type, the interaction strength is small at low energies but increases at higher energies towards a finite constant value of the coupling. The net effect is to partially offset direct detection constraints without affecting thermal freeze-out at higher energies. High-energy collider and indirect annihilation searches are the primary ways to constrain or discover asymptotically safe dark matter.

  20. Baryonic Dark Halos: Machos and Cold Gas?

    OpenAIRE

    Gerhard, Ortwin; Silk, Joseph

    1995-01-01

    We consider the possibility that the dark matter in the halos of galaxies may be in the form of clusters of \\macho s within which are embedded cold, dense gas clouds. Microlensing experiments have found evidence that the Galactic halo contains up to half of its mass in the form of low-mass \\macho s. A number of observational and dynamical arguments point to the existence of hitherto unobserved cold gas around galaxies. We show that the cold gas can be stabilized by \\macho\\ clusters. Within th...

  1. Dark matter: Theoretical perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.S. (Chicago Univ., IL (United States). Enrico Fermi Inst. Fermi National Accelerator Lab., Batavia, IL (United States))

    1993-01-01

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for new physics.'' The compelling candidates are: a very light axion ( 10[sup [minus]6] eV--10[sup [minus]4] eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

  2. Dark matter: Theoretical perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.S. [Chicago Univ., IL (United States). Enrico Fermi Inst.]|[Fermi National Accelerator Lab., Batavia, IL (United States)

    1993-01-01

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for ``new physics.`` The compelling candidates are: a very light axion ( 10{sup {minus}6} eV--10{sup {minus}4} eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos.

  3. Dark matter: Theoretical perspectives

    International Nuclear Information System (INIS)

    I both review and make the case for the current theoretical prejudice: a flat Universe whose dominant constituent is nonbaryonic dark matter, emphasizing that this is still a prejudice and not yet fact. The theoretical motivation for nonbaryonic dark matter is discussed in the context of current elementary-particle theory, stressing that: (1) there are no dark matter candidates within the standard model of particle physics; (2) there are several compelling candidates within attractive extensions of the standard model of particle physics; and (3) the motivation for these compelling candidates comes first and foremost from particle physics. The dark-matter problem is now a pressing issue in both cosmology and particle physics, and the detection of particle dark matter would provide evidence for ''new physics.'' The compelling candidates are: a very light axion ( 10-6 eV--10-4 eV); a light neutrino (20 eV--90 eV); and a heavy neutralino (10 GeV--2 TeV). The production of these particles in the early Universe and the prospects for their detection are also discussed. I briefly mention more exotic possibilities for the dark matter, including a nonzero cosmological constant, superheavy magnetic monopoles, and decaying neutrinos

  4. Hidden Hot Dark Matter as Cold Dark Matter

    OpenAIRE

    Sigurdson, Kris

    2009-01-01

    We show that hidden hot dark matter, hidden-sector dark matter with interactions that decouple when it is relativistic, is a viable dark matter candidate provided it has never been in thermal equilibrium with the particles of the standard model. This hidden hot dark matter may reheat to a lower temperature and number density than the visible Universe and thus account, simply with its thermal abundance, for all the dark matter in the Universe while evading the typical constra...

  5. The dark matter of gravitational lensing

    CERN Document Server

    Massey, Richard; Richard, Johan

    2010-01-01

    We review progress in understanding dark matter by astrophysics, and particularly via the effect of gravitational lensing. Evidence from many different directions now implies that five sixths of the material content of the universe is in this mysterious form, separate from and beyond the ordinary "baryonic" particles in the standard model of particle physics. Dark matter appears not to interact via the electromagnetic force, and therefore neither emits nor reflects light. However, it definitely does interact via gravity, and has played the most important role in shaping the Universe on large scales. The most successful technique with which to investigate it has so far been gravitational lensing. The curvature of space-time near any gravitating mass (including dark matter) deflects passing rays of light - observably shifting, distorting and magnifying the images of background galaxies. Measurements of such effects currently provide constraints on the mean density of dark matter, and its density relative to bar...

  6. Astrophysical Constraints on Dark Matter

    OpenAIRE

    Tao, Charling

    2011-01-01

    Astrophysics gives evidence for the existence of Dark Matter and puts constraints on its nature. The Cold Dark Matter model has become "standard" cosmology combined with a cosmological constant. There are indications that "Cold" Dark Matter could be "warmer" than initially discussed. This paper reviews the main information on the Cold/Warm nature of Dark Matter.

  7. Flavored Dark Matter: A Review

    OpenAIRE

    Kile, Jennifer

    2013-01-01

    The current status of flavored dark matter is reviewed. We discuss the main experimental constraints on models of flavored dark matter and survey some possible considerations which are relevant for the constructions of models. We then review the application of existing flavor principles to dark matter, with an emphasis on minimal flavor violation, and discuss implications of flavored dark matter on collider phenomenology.

  8. Light Dark Matter and Dark Radiation

    CERN Document Server

    Heo, Jae Ho

    2015-01-01

    The light dark matter particles freeze out after neutrino decoupling. If the dark matter particle couples to neutrino or electromagnetic plasma, the late time entropy production by dark matter annihilations can change the neutrino-to-photon temperature ratio, and equally effective number of neutrinos. We study the effect of dark matter annihilations in the thermal equilibrium approximation and non-equilibrium method (freeze-out mechanism), and constrain both results with Planck observations. We demonstrate that the bound of dark matter mass and the possibility of the existence of extra radiation particles are more tightly constrained in the non-equilibrium method.

  9. Resonant SIMP dark matter

    OpenAIRE

    Soo-Min Choi; Hyun Min Lee

    2016-01-01

    We consider a resonant SIMP dark matter in models with two singlet complex scalar fields charged under a local dark U(1)D. After the U(1)D is broken down to a Z5 discrete subgroup, the lighter scalar field becomes a SIMP dark matter which has the enhanced 3→2 annihilation cross section near the resonance of the heavier scalar field. Bounds on the SIMP self-scattering cross section and the relic density can be fulfilled at the same time for perturbative couplings of SIMP. A small gauge kinetic...

  10. Dark Matter Annihilations in the Large Magellanic Cloud

    OpenAIRE

    Gondolo, P.

    1993-01-01

    The flat rotation curve obtained for the outer star clusters of the Large Magellanic Cloud is suggestive of an LMC dark matter halo. From the composite HI and star cluster rotation curve, I estimate the parameters of an isothermal dark matter halo added to a `maximum disk.' I then examine the possibility of detecting high energy gamma-rays from non-baryonic dark matter annihilations in the central region of the Large Magellanic Cloud.

  11. Levitating dark matter

    Science.gov (United States)

    Kaloper, Nemanja; Padilla, Antonio

    2009-10-01

    A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark U(1)' charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of dark matter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra `antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic w dark energy, or superhorizon effects.

  12. Cogenerating and Pre-annihilating Dark Matter by a New Gauge Interaction

    OpenAIRE

    S.M. Barr; Scherrer, Robert J.

    2015-01-01

    In asymmetric dark matter scenarios, there must be a mechanism to annihilate the anti-dark matter. It is proposed here that a new non-abelian gauge interaction can both cogenerate asymmetric dark matter with baryonic matter through its sphaleron processes, and can pre-annihilate the anti-dark matter efficiently. The resulting scenario can naturally generate either cold or warm dark matter.

  13. Radion as a possible dark matter candidate

    CERN Document Server

    Chakraborty, Sumanta

    2015-01-01

    The discrepancy between observed virial and baryonic mass in galaxy clusters have lead to the missing mass problem. To resolve this, a new, non-baryonic matter field, known as dark matter has been invoked. However, till date no possible constituents of the dark matter components are known. This has led to various models, by modifying gravity at large distances to explain the missing mass problem. The modification to gravity appears very naturally when effective field theory on a lower dimensional manifold, embedded in a higher dimensional spacetime is considered. It has been shown that in a scenario with two lower dimensional manifolds separated by a finite distance is capable to address the missing mass problem, which in turn determines the kinematics of the brane separation.

  14. Dark and Light: Unifying the Origins of Dark and Visible Matter

    OpenAIRE

    Shuve, Brian

    2012-01-01

    The Standard Model of particle physics can account for neither the dark matter dominating the universe's matter density, nor the baryon asymmetry that leads to the visible matter density. This dissertation explores models of new physics that connect dark matter to baryogenesis and can naturally account for the observed quantities of both types of matter. Special emphasis is given to models incorporating new weak-scale physics, as such models often predict signatures at present and upcoming ex...

  15. Collider limits on dark matter

    OpenAIRE

    Kopp, Joachim

    2011-01-01

    Dark matter pair production at high energy colliders may leave observable signatures in the energy and momentum spectra of the objects recoiling against the dark matter. We discuss signatures of Dark Matter in the jets + missing energy and photon + missing energy channels at the Tevatron and at LEP. Working in a largely model-independent effective theory framework, we can convert the collider bounds into constraints on the dark matter-nucleon scattering cross section and on the dark matter an...

  16. Dilaton-assisted Dark Matter

    OpenAIRE

    Bai, Yang; Carena, Marcela; Lykken, Joseph

    2009-01-01

    A dilaton could be the dominant messenger between Standard Model fields and dark matter. The measured dark matter relic abundance relates the dark matter mass and spin to the conformal breaking scale. The dark matter-nucleon spin-independent cross section is predicted in terms of the dilaton mass. We compute the current constraints on the dilaton from LEP and Tevatron experiments, and the gamma-ray signal from dark matter annihilation to dilatons that could be observed by Fermi-LAT.

  17. GUTzilla Dark Matter

    CERN Document Server

    Harigaya, Keisuke; Lou, Hou Keong

    2016-01-01

    Motivated by gauge coupling unification and dark matter, we present an extension to the Standard Model where both are achieved by adding an extra new matter multiplet. Such considerations lead to a Grand Unified Theory with very heavy WIMPzilla dark matter, which has mass greater than ~10^7 GeV and must be produced before reheating ends. Naturally, we refer to this scenario as GUTzilla dark matter. Here we present a minimal GUTzilla model, adding a vector-like quark multiplet to the Standard Model. Proton decay constraints require the new multiplet to be both color and electroweak charged, which prompts us to include a new confining SU(3) gauge group that binds the multiplet into a neutral composite dark matter candidate. Current direct detection constraints are evaded due to the large dark matter mass; meanwhile, next-generation direct detection and proton decay experiments will probe much of the parameter space. The relic abundance is strongly dependent on the dynamics of the hidden confining sector, and we...

  18. Influence of baryons on spatial distribution of matter: higher order correlation functions

    CERN Document Server

    Zhu, Xiaojun

    2012-01-01

    Baryonic physical processes could leave non-negligible imprint on cosmic matter distribution pattern. Series of high precision simulation data sets with identical initial condition are employed for count-in-cell (CIC) analysis, including one N-body dark matter run, one with adiabatic gas only and one with dissipative processes. Variances and higher order correlation functions of dark matter and gas are estimated. It is found that baryon physical processes mainly affected dark matter distribution at scales less than $1h^{-1}$Mpc. In comparison with the pure dark matter run, adiabatic process alone strengthens variance of dark matter by \\sim 10% at scale $0.1h^{-1}$Mpc, while $S_n$s of dark matter deviate from pure dark matter case only mildly at a few percentages. Dissipative gas run does not differ much to the adiabatic run in dark matter variance, but renders significantly different $S_n$ parameters of dark matter, bringing about more than 10% enhancement to $S_3$ at $0.1h^{-1}$Mpc and $z=0$. Distribution pa...

  19. Thermal Relic Dark Matter Beyond the Unitarity Limit

    OpenAIRE

    Harigaya, Keisuke; Ibe, Masahiro; Kaneta, Kunio; Nakano, Wakutaka; Suzuki, Motoo

    2016-01-01

    We discuss a simple model of thermal relic dark matter whose mass can be much larger than the so-called unitarity limit on the mass of point-like particle dark matter. The model consists of new strong dynamics with one flavor of fermions in the fundamental representation which is much heavier than the dynamical scale of the new strong dynamics. Dark matter is identified with the lightest baryonic hadron of the new dynamics. The baryonic hadrons annihilate into the mesonic hadrons of the new s...

  20. Can Dark Matter Decay in Dark Energy?

    OpenAIRE

    Pereira, S. H.; Jesus, J. F.

    2008-01-01

    We analyze the interaction between Dark Energy and Dark Matter from a thermodynamical perspective. By assuming they have different temperatures, we study the possibility of occurring a decay from Dark Matter into Dark Energy, characterized by a negative parameter $Q$. We find that, if at least one of the fluids has non vanishing chemical potential, for instance $\\mu_x0$, the decay is possible, where $\\mu_x$ and $\\mu_{dm}$ are the chemical potentials of Dark Energy and Dark Matter, respectivel...

  1. Dark matter in the universe

    International Nuclear Information System (INIS)

    What is the quantity and composition of material in the Universe? This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: Most of the material in the Universe does not give off detectable radiation, i.e., is ''dark;'' the dark matter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments--structure formation, the temporal Copernican principle, and inflation--and by some observational data. If Ω is indeed unity--or even just significantly greater than 0.1--then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10-6 eV to 10-4 eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either being planned or are underway. 63 refs

  2. Dark matter in the universe

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.S. (Fermi National Accelerator Lab., Batavia, IL (USA) Chicago Univ., IL (USA). Enrico Fermi Inst.)

    1990-11-01

    What is the quantity and composition of material in the Universe This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: Most of the material in the Universe does not give off detectable radiation, i.e., is dark;'' the dark matter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments--structure formation, the temporal Copernican principle, and inflation--and by some observational data. If {Omega} is indeed unity--or even just significantly greater than 0.1--then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10{sup {minus}6} eV to 10{sup {minus}4} eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either being planned or are underway. 63 refs.

  3. Dark matter in the Universe

    Energy Technology Data Exchange (ETDEWEB)

    Turner, M.S. (Fermi National Accelerator Lab., Batavia, IL (USA) Chicago Univ., IL (USA). Enrico Fermi Inst.)

    1991-03-01

    What is the quantity and composition of material in the universe This is one of the most fundamental questions we can ask about the universe, and its answer bears on a number of important issues including the formation of structure in the universe, and the ultimate fate and the earliest history of the universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand: most of the material in the universe does not give off detectable radiation, i.e., is dark;'' the dark matter associated with bright galaxies contributes somewhere between 10% and 30% of the critical density (by comparison luminous matter contributes less than 1%); baryonic matter contributes between 1.1% and 12% of critical. The case for the spatially-flat, Einstein-de Sitter model is supported by three compelling theoretical arguments -- structure formation, the temporal Copernican principle, and inflation -- and by some observational data. If {Omega} is indeed unity--or even just significantly greater than 0.1--then there is a strong case for a universe comprised of nonbaryonic matter. There are three well motivated particle dark-matter candidates: an axion of mass 10{sup {minus}6} eV to 10{sup {minus}4} eV; a neutralino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either being planned or are underway. 71 refs., 6 figs.

  4. Dark energy and light WIMP dark matter from the cosmological viewpoint

    OpenAIRE

    Kuzmichev, V. E.; Kuzmichev, V. V.

    2010-01-01

    We give an estimation of the masses of light dark matter particle and dark energy quasiparticle which can be extracted from the astrophysical data about the contributions of baryon, dark matter, and dark energy densities to the total matter-energy density budget in our universe. We use the quantum cosmological model in which dark energy is a condensate of quantum oscillations of primordial scalar field. The dark energy quasiparticle with the mass ~ 15 GeV is consistent with the 7-year WMAP an...

  5. Constraints on the Coupling between Dark Energy and Dark Matter from CMB data

    CERN Document Server

    Murgia, Riccardo; Fornengo, Nicolao

    2016-01-01

    We investigate a phenomenological non-gravitational coupling between dark energy and dark matter, where the interaction in the dark sector is parameterized as an energy transfer either from dark matter to dark energy or the opposite. The models are constrained by a whole host of updated cosmological data: cosmic microwave background temperature anisotropies and polarization, high-redshift supernovae, baryon acoustic oscillations, redshift space distortions and gravitational lensing. Both models are found to be compatible with all cosmological observables, but in the case where dark matter decays into dark energy, the tension with the independent determinations of $H_0$ and $\\sigma_8$, already present for standard cosmology, increases: this model in fact predicts lower $H_0$ and higher $\\sigma_8$, mostly as a consequence of the higher amount of dark matter at early times, leading to a stronger clustering during the evolution. Instead, when dark matter is fed by dark energy, the reconstructed values of $H_0$ an...

  6. The Compressed Baryonic Matter experiment at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Senger, P. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2011-07-15

    The Compressed Baryonic Matter (CBM) experiment will be one of the major scientific pillars of the future Facility for Antiproton and Ion Research (FAIR) in Darmstadt. The goal of the CBM research program is to explore the QCD phase diagram in the region of high baryon densities using high-energy nucleus-nucleus collisions. This includes the study of the equation-of-state of nuclear matter at high densities, and the search for the deconfinement and chiral phase transitions. The CBM detector is designed to measure both bulk observables with large acceptance and rare diagnostic probes such as charmed particles and vector mesons decaying into lepton pairs. The layout and the physics performance of the proposed CBM experimental facility will be discussed.

  7. Ghost Dark Matter

    CERN Document Server

    Furukawa, Tomonori; Ichiki, Kiyotomo; Sugiyama, Naoshi; Mukohyama, Shinji

    2010-01-01

    We revisit ghost dark matter, the possibility that ghost condensation may serve as an alternative to dark matter. In particular, we investigate the Friedmann-Robertson-Walker (FRW) background evolution and the large-scale structure (LSS) in the $\\Lambda$GDM universe, i.e. a late-time universe dominated by a cosmological constant and ghost dark matter. The FRW background of the $\\Lambda$GDM universe is indistinguishable from that of the standard $\\Lambda$CDM universe if $M\\gtrsim 1 {\\rm eV}$, where $M$ is the scale of spontaneous Lorentz breaking. From the LSS we find a stronger bound: $M\\gtrsim 10 {\\rm eV}$. For smaller $M$, ghost dark matter would have non-negligible sound speed after the matter-radiation equality, and thus the matter power spectrum would significantly differ from observation. These bounds are compatible with the phenomenological upper bound $M\\lesssim 100 {\\rm GeV}$ known in the literature.

  8. Co-Decaying Dark Matter

    OpenAIRE

    Dror, Jeff Asaf; Kuflik, Eric; Ng, Wee Hao

    2016-01-01

    We propose a new mechanism for thermal dark matter freezeout, termed Co-Decaying Dark Matter. Multi-component dark sectors with degenerate particles and out-of-equilibrium decays can co-decay to obtain the observed relic density. The dark matter density is exponentially depleted through the decay of nearly degenerate particles, rather than from Boltzmann suppression. The relic abundance is set by the dark matter annihilation cross-section, which is predicted to be boosted, and the decay rate ...

  9. WIMP and Axion Dark Matter

    OpenAIRE

    Kamionkowski, Marc

    1997-01-01

    There is almost universal agreement among cosmologists that most of the matter in the Universe is dark, and there are very good reasons to believe that most of this dark matter must be nonbaryonic. The two leading candidates for this dark matter are axions and weakly-interacting massive particles (WIMPs), such as the neutralino in supersymmetric extensions of the standard model. I discuss the arguments for these two dark-matter candidates and review techniques for discovery of these dark-matt...

  10. Rotating dark matter solution admitting dark fluid

    OpenAIRE

    Ibohal, Ng.; Ishwarchandra, Ngangbam; Singh, K. Yugindro

    2009-01-01

    In this paper we present an exact solution of Einstein's fields equations describing dark matter possessing dark energy with negative pressure and energy equation of state parameter having minus sign.

  11. WISPy cold dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Arias, Paola [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica; Cadamuro, Davide; Redondo, Javier [Max-Planck-Institut fuer Physik, Muenchen (Germany); Goodsell, Mark [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Jaeckel, Joerg [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-01-15

    Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold dark matter population until today. We find that, both for ALPs and HPs whose dominant interactions with the standard model arise from couplings to photons, a huge region in the parameter spaces spanned by photon coupling and ALP or HP mass can give rise to the observed cold dark matter. Remarkably, a large region of this parameter space coincides with that predicted in well motivated models of fundamental physics. A wide range of experimental searches - exploiting haloscopes (direct dark matter searches exploiting microwave cavities), helioscopes (searches for solar ALPs or HPs), or light-shining-through-a-wall techniques - can probe large parts of this parameter space in the foreseeable future. (orig.)

  12. Selfish Dark Matter

    CERN Document Server

    D'Agnolo, Raffaele Tito

    2015-01-01

    We present a mechanism where a particle asymmetry in one sector is used to generate an asymmetry in another sector. The two sectors are not coupled through particle number violating interactions and are not required to be in thermal contact with each other. When this mechanism is applied to baryogenesis in asymmetric dark matter models, we find that the dark matter particles can be extremely light, e.g. much lighter than an eV, and that in some cases there is no need to annihilate away the symmetric component of dark matter. We discuss a concrete realization of the mechanism with signals in direct detection, at the LHC, at $B$-factories or future beam dump experiments.

  13. Axion Dark Matter Searches

    CERN Document Server

    Stern, I

    2014-01-01

    Nearly all astrophysical and cosmological data point convincingly to a large component of cold dark matter in the Universe. The axion particle, first theorized as a solution to the strong charge-parity problem of quantum chromodynamics, has been established as a prominent CDM candidate. Cosmic observation and particle physics experiments have bracketed the unknown mass of the axion between approximately a $\\mu$eV and a meV. The Axion Dark Matter eXperiement (ADMX) has successfully completed searches between 1.9 and 3.7 $\\mu$eV down to the KSVZ photon-coupling limit. ADMX and the Axion Dark Matter eXperiement High-Frequency (ADMX-HF) will search for axions at weaker coupling and/or higher frequencies within the next few years. Status of the experiments, current research and development, and projected mass-coupling exclusion limits are presented.

  14. Weak lensing, dark matter and dark energy

    OpenAIRE

    Huterer, Dragan

    2010-01-01

    Weak gravitational lensing is rapidly becoming one of the principal probes of dark matter and dark energy in the universe. In this brief review we outline how weak lensing helps determine the structure of dark matter halos, measure the expansion rate of the universe, and distinguish between modified gravity and dark energy explanations for the acceleration of the universe. We also discuss requirements on the control of systematic errors so that the systematics do not appreciably degrade the p...

  15. Unification of Dark Energy and Dark Matter

    OpenAIRE

    Takahashi, Fuminobu; Yanagida, T. T.

    2005-01-01

    We propose a scenario in which dark energy and dark matter are described in a unified manner. The ultralight pseudo-Nambu-Goldstone (pNG) boson, A, naturally explains the observed magnitude of dark energy, while the bosonic supersymmetry partner of the pNG boson, B, can be a dominant component of dark matter. The decay of B into a pair of electron and positron may explain the 511 keV gamma ray from the Galactic Center.

  16. Dark matter in the universe

    Science.gov (United States)

    Turner, Michael S.

    1991-01-01

    What is the quantity and composition of material in the Universe? This is one of the most fundamental questions we can ask about the Universe, and its answer bears on a number of important issues including the formation of structure in the Universe, and the ultimate fate and the earliest history of the Universe. Moreover, answering this question could lead to the discovery of new particles, as well as shedding light on the nature of the fundamental interactions. At present, only a partial answer is at hand. Most of the radiation in the Universe does not give off detectable radiation; it is dark. The dark matter associated with bright galaxies contributes somewhere between 10 and 30 percent of the critical density; baryonic matter contributes between 1.1 and 12 percent of the critical. The case for the spatially flat, Einstein-de Sitter model is supported by three compelling theoretical arguments - structure formation, the temporal Copernican principle, and inflation - and by some observational data. If Omega is indeed unity, or even just significantly greater than 0.1, then there is a strong case for a Universe comprised of nonbaryonic matter. There are three well motivated particle dark matter candidates: an axion of mass 10 (exp -6) eV to 10 (exp -4) eV; a neutrino of mass 10 GeV to about 3 TeV; or a neutrino of mass 20 eV to 90 eV. All three possibilities can be tested by experiments that are either planned or are underway.

  17. Levitating Dark Matter

    OpenAIRE

    Kaloper, Nemanja; Padilla, Antonio

    2009-01-01

    A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark $U(1)'$ charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of dark matter agglomerates may yield s...

  18. Dark Matter and MOOCs

    CERN Document Server

    Salucci, Paolo

    2013-01-01

    To teach the topic of Dark Matter in Galaxies to undergraduate and PhD students is not easy, one reason being that the scientific community has not converged yet to a generally shared knowledge. We argue that the teaching of this topic and its subsequent scientific progress may benefit by Massive Online and Open Courses. The reader of this paper can express his/her opinion on this by means of a confidence vote at: https://moocfellowship.org/submissions/dark-matter-in-galaxies-the-last-mystery

  19. Asymmetric condensed dark matter

    Science.gov (United States)

    Aguirre, Anthony; Diez-Tejedor, Alberto

    2016-04-01

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.

  20. The dark universe dark matter and dark energy

    CERN Document Server

    CERN. Geneva

    2008-01-01

    According to the standard cosmological model, 95% of the present mass density of the universe is dark: roughly 70% of the total in the form of dark energy and 25% in the form of dark matter. In a series of four lectures, I will begin by presenting a brief review of cosmology, and then I will review the observational evidence for dark matter and dark energy. I will discuss some of the proposals for dark matter and dark energy, and connect them to high-energy physics. I will also present an overview of an observational program to quantify the properties of dark energy.

  1. Hidden Hot Dark Matter as Cold Dark Matter

    OpenAIRE

    Sigurdson, Kris

    2009-01-01

    We show that hidden hot dark matter, hidden-sector dark matter with interactions that decouple when it is relativistic, is a viable dark matter candidate provided it has never been in thermal equilibrium with the particles of the standard model. This hidden hot dark matter may reheat to a lower temperature and number density than the visible Universe and thus account, simply with its thermal abundance, for all the dark matter in the Universe while evading the typical constraints on hot dark m...

  2. Weak lensing: Dark Matter, Dark Energy and Dark Gravity

    OpenAIRE

    Heavens, Alan

    2009-01-01

    In this non-specialist review I look at how weak lensing can provide information on the dark sector of the Universe. The review concentrates on what can be learned about Dark Matter, Dark Energy and Dark Gravity, and why. On Dark Matter, results on the confrontation of theoretical profiles with observation are reviewed, and measurements of neutrino masses discussed. On Dark Energy, the interest is whether this could be Einstein's cosmological constant, and prospects for high-precision studies...

  3. Light Dark Matter and Dark Radiation

    OpenAIRE

    Heo, Jae Ho; Kim, C. S.

    2015-01-01

    Light dark-matter ($M\\leq20$ MeV) particles freeze out after neutrino decoupling. If the dark-matter particle couples to a neutrino or an electromagnetic plasma, the late time entropy production from dark-matter annihilation can change the neutrino-to-photon temperature ratio, and equally the effective number of neutrinos $N_{eff}$. We study the non-equilibrium effects of dark-matter annihilation on the $N_{eff}$ and the effects by using a thermal equilibrium approximation. Both results are c...

  4. Alternatives to Dark Matter (?)

    OpenAIRE

    Aguirre, Anthony

    2003-01-01

    It has long been known that Newtonian dynamics applied to the visible matter in galaxies and clusters does not correctly describe the dynamics of those systems. While this is generally taken as evidence for dark matter it is in principle possible that instead Newtonian dynamics (and with it General Relativity) breaks down in these systems. Indeed there have been a number of proposals as to how standard gravitational dynamics might be modified so as to correctly explain galactic dynamics witho...

  5. Cold Dark Matter Models

    OpenAIRE

    Dodelson, Scott; Gates, Evalyn; Turner, Michael S.

    1996-01-01

    Motivated by inflation, the theory of big-bang nucleosynthesis and the quest for a deeper understanding of the fundamental forces and particles, a very successful paradigm for the development of structure in the Universe has evolved. It holds that most of the matter exists in the form of slowly moving elementary particles left over from the earliest moments (cold dark matter or CDM) and that the small density inhomogeneities that seed structure formation arose from quantum fluctuations around...

  6. Spherical Cows in Dark Matter Indirect Detection

    OpenAIRE

    Bernal, Nicolás; Necib, Lina; Slatyer, Tracy R.

    2016-01-01

    Dark matter (DM) halos have long been known to be triaxial, but in studies of possible annihilation and decay signals they are often treated as approximately spherical. In this work, we examine the asymmetry of potential indirect detection signals of DM annihilation and decay, exploiting the large statistics of the hydrodynamic simulation Illustris. We carefully investigate the effects of the baryons on the sphericity of annihilation and decay signals for both the case where the observer is a...

  7. Very Cold Gas and Dark Matter

    OpenAIRE

    Combes, F.; Pfenniger, D.

    1996-01-01

    We have recently proposed a new candidate for baryonic dark matter: very cold molecular gas, in near-isothermal equilibrium with the cosmic background radiation at 2.73 K. The cold gas, of quasi-primordial abundances, is condensed in a fractal structure, resembling the hierarchical structure of the detected interstellar medium. We present some perspectives of detecting this very cold gas, either directly or indirectly. The H$_2$ molecule has an "ultrafine" structure, due to the interaction be...

  8. Dark Matter searches with the ATLAS Detector

    CERN Document Server

    Hooberman, Benjamin Henry; The ATLAS collaboration

    2016-01-01

    The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If DM interacts non-gravitationally with the Standard Model, it could be produced at the LHC, escaping the detector and leaving missing transverse momentum (MET) as a signature. Recent results from the ATLAS detector will be presented, based on events with large MET accompanied by a variety of other objects.

  9. Identification of all dark matter as black holes

    International Nuclear Information System (INIS)

    For the universe I use dimensionless entropy S/k = ln Ω for which the most convenient unit is the googol (10100) and take all dark matter as black holes whereupon the present entropy is about a thousand googols independently of whether dark energy possesses entropy. While the energy of the universe has been established to be about 0.04 baryons, 0.24 dark matter and 0.72 dark energy, the cosmological entropy is almost entirely, about (1−10−15), from black holes and only 10−15 from everything else. This identification of all dark matter as black holes is natural in statistical mechanics

  10. Dark matter detection

    Science.gov (United States)

    Baudis, Laura

    2016-08-01

    More than 80 years after its first postulation in modern form, the existence and distribution of dark matter in our Universe is well established. Dark matter is the gravitational glue that holds together galaxies, galaxy clusters and structures on the largest cosmological scales, and an essential component to explain the observed fluctuations in the cosmic microwave background. Yet its existence is inferred indirectly, through its gravitational influence on luminous matter, and its nature is not known. A viable hypothesis is that dark matter is made of new, elementary particles, with allowed masses and interaction strengths spanning a wide range. Two well-motivated classes of candidates are axions and weakly interacting massive particles (WIMPs), and experimental efforts have now reached sensitivities that allow them to test this hypothesis. Axions, produced non-thermally in the early Universe, can be detected by exploiting their predicted couplings to photons and electrons. WIMPs can be detected directly by looking for their collisions with atomic nuclei ultra-low background detectors, or indirectly, through the observation of their annihilation products such as neutrinos, gamma rays, positrons and antiprotons over the astrophysical background. A complementary method is the production of dark matter particles at colliders such as the Large Hadron Collider, where they could be observed indirectly via missing transverse energy, or via associated particle production. I will review the main experimental efforts to search for dark matter particles, and the existing constraints on the interaction cross sections. I will also discuss future experiments, their complementarity and their ability to measure the properties of these particles.

  11. The Dark Matter Telescope

    CERN Document Server

    Tyson, J A; Angel, J R P; Wittman, David

    2001-01-01

    Weak gravitational lensing enables direct reconstruction of dark matter maps over cosmologically significant volumes. This research is currently telescope-limited. The Dark Matter Telescope (DMT) is a proposed 8.4 m telescope with a 3 degree field of view, with an etendue of 260 $(m. degree)^2$, ten times greater than any other current or planned telescope. With its large etendue and dedicated observational mode, the DMT fills a nearly unexplored region of parameter space and enables projects that would take decades on current facilities. The DMT will be able to reach 10-sigma limiting magnitudes of 27-28 magnitude in the wavelength range .3 - 1 um over a 7 square degree field in 3 nights of dark time. Here we review its unique weak lensing cosmology capabilities and the design that enables those capabilities.

  12. Inflatable Dark Matter

    CERN Document Server

    Davoudiasl, Hooman; McDermott, Samuel D

    2016-01-01

    We describe a general scenario, dubbed "Inflatable Dark Matter", in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early universe. The overproduction of dark matter that is predicted within many otherwise well-motivated models of new physics can be elegantly remedied within this context, without the need to tune underlying parameters or to appeal to anthropic considerations. Thermal relics that would otherwise be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the non-thermal abundance of GUT or Planck scale axions can be brought to acceptable levels, without invoking anthropic tuning of initial conditions. A period of late-time inflation could have occurred over a wide range of scales from ~ MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the...

  13. Dark matter on top

    International Nuclear Information System (INIS)

    We consider a simplified model of fermionic dark matter which couples exclusively to the right-handed top quark via a renormalizable interaction with a color-charged scalar. We first compute the relic abundance of this type of dark matter and investigate constraints placed on the model parameter space by the latest direct detection data. We also perform a detailed analysis for the production of dark matter at the LHC for this model. We find several kinematic variables that allow for a clean signal extraction and we show that the parameter space of this model will be well probed during LHC Run-II. Finally, we investigate the possibility of detecting this type of dark matter via its annihilations into gamma rays. We compute the continuum and the line emission (which includes a possible ''Higgs in Space!'' line) and its possible discovery by future gamma-ray telescopes. We find that the annihilation spectrum has distinctive features which may distinguish it from other models

  14. Template Composite Dark Matter

    DEFF Research Database (Denmark)

    Drach, Vincent; Hietanen, Ari; Pica, Claudio;

    2015-01-01

    We present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. We discuss how the model can be used as a template for composite Dark Matter (DM). We estimate one particular interaction of the DM candidate with the Standard Model : the interaction through photon...

  15. Interacting dark matter disguised as warm dark matter

    International Nuclear Information System (INIS)

    We explore some of the consequences of dark-matter-photon interactions on structure formation, focusing on the evolution of cosmological perturbations and performing both an analytical and a numerical study. We compute the cosmic microwave background anisotropies and matter power spectrum in this class of models. We find, as the main result, that when dark matter and photons are coupled, dark matter perturbations can experience a new damping regime in addition to the usual collisional Silk damping effect. Such dark matter particles (having quite large photon interactions) behave like cold dark matter or warm dark matter as far as the cosmic microwave background anisotropies or matter power spectrum are concerned, respectively. These dark-matter-photon interactions leave specific imprints at sufficiently small scales on both of these two spectra, which may allow us to put new constraints on the acceptable photon-dark-matter interactions. Under the conservative assumption that the abundance of 1012M· galaxies is correctly given by the cold dark matter, and without any knowledge of the abundance of smaller objects, we obtain the limit on the ratio of the dark-matter-photon cross section to the dark matter mass σγ-DM/mDM -6σTh/(100 GeV)≅6x10-33 cm2 GeV-1

  16. DARK MATTER AND DARK ENERGY OF THE UNIVERSE INRIA-SACLAYS Version

    OpenAIRE

    Delort, Thierry

    2016-01-01

    In this article, we propose a new model of dark matter. According to this new model, dark matter is a substance, that is a new physical element not constituted of classical particles, called dark substance and filling the Universe. Assuming some very simple physical properties to this dark substance, we theoretically justify the flat rotation curve of galaxies and the baryonic Tully-Fisher's law. Then using the new model of dark matter we are naturally led to propose a new geometrical model o...

  17. Dark Matter Halos from the Inside Out

    CERN Document Server

    Taylor, James E

    2010-01-01

    The balance of evidence indicates that individual galaxies and groups or clusters of galaxies are embedded in enormous distributions of cold, weakly interacting dark matter. These dark matter 'halos' provide the scaffolding for all luminous structure in the universe, and their properties comprise an essential part of the current cosmological model. I review the internal properties of dark matter halos, focussing on the simple, universal trends predicted by numerical simulations of structure formation. Simulations indicate that halos should all have roughly the same spherically-averaged density profile and kinematic structure, and predict simple distributions of shape, formation history and substructure in density and kinematics, over an enormous range of halo mass and for all common variants of the concordance cosmology. I describe observational progress towards testing these predictions by measuring masses, shapes, profiles and substructure in real halos, using baryonic tracers or gravitational lensing. An i...

  18. Dark matter from unification

    DEFF Research Database (Denmark)

    Kainulainen, Kimmo; Tuominen, Kimmo; Virkajärvi, Jussi Tuomas

    2013-01-01

    We consider a minimal extension of the Standard Model (SM), which leads to unification of the SM coupling constants, breaks electroweak symmetry dynamically by a new strongly coupled sector and leads to novel dark matter candidates. In this model, the coupling constant unification requires...... eigenstates of this sector and determine the resulting relic density. The results are constrained by available data from colliders and direct and indirect dark matter experiments. We find the model viable and outline briefly future research directions....... the existence of electroweak triplet and doublet fermions singlet under QCD and new strong dynamics underlying the Higgs sector. Among these new matter fields and a new right handed neutrino, we consider the mass and mixing patterns of the neutral states. We argue for a symmetry stabilizing the lightest mass...

  19. Phase transitions and dark matter problems

    International Nuclear Information System (INIS)

    The possible relationships between phase transitions in the early universe and dark matter problems are discussed. It is shown that there are at least 3 distinct cosmological dark matter problems 1) halos; 2) galaxy formation and clustering; and 3) Ω = 1, each emphasizing different attributes for the dark matter. At least some of the dark matter must by baryonic but if problems 2 and 3 are real they seem to also require non-baryonic material. However, if seeds are generated at the quark-hadron-chiral symmetry transition then alternatives to the standard scenarios may occur. At present no simple simultaneous solution (neither ''hot'', ''warm'', nor ''cold'') exists for all 3 problems, but non-standard solutions with strings, decaying particles or light not tracing to mass may work. An alternative interpretation of the relationship of the cluster-cluster and galaxy-galaxy correlation functions using renormalized scaling is mentioned. In this interpretation galaxies are more strongly correlated and the cluster-cluster function is not expected to go negative until > or approx. 200 Mpc. Possible phase transition origins for the cluster-cluster renormalized scale are presented as ways to obtain a dimension 1.2 fractal. (orig.)

  20. Dark matter, neutrinos, and our solar system

    CERN Document Server

    Prakash, Nirmala

    2013-01-01

    Dark Matter, Neutrinos, and Our Solar System is a unique enterprise that should be viewed as an important contribution to our understanding of dark matter, neutrinos and the solar system. It describes these issues in terms of links, between cosmology, particle and nuclear physics, as well as between cosmology, atmospheric and terrestrial physics. It studies the constituents of dark matter (classified as hot warm and cold) first in terms of their individual structures (baryonic and non-baryonic, massive and non-massive, interacting and non-interacting) and second, in terms of facilities available to detect these structures (large and small). Neutrinos (an important component of dark matter) are treated as a separate entity. A detailed study of these elusive (sub-atomic) particles is done, from the year 1913 when they were found as byproducts of beta decay -- until the discovery in 2007 which confirmed that neutrino flavors were not more than three (as speculated by some). The last chapter of the book details t...

  1. Introduction to Dark Energy and Dark Matter

    OpenAIRE

    Frampton, Paul H.

    2005-01-01

    In an introductory manner, the nature of dark energy is addressed, how it is observed and what further tests are needed to reconstruct its properties. Several theoretical approaches to dark energy will be discussed. Finally, the dark matter, especially WIMPs, is introduced.

  2. Levitating dark matter

    International Nuclear Information System (INIS)

    A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark U(1)' charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of dark matter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra 'antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic w < −1. They can also lead to a local variation of galaxy-galaxy forces, yielding a larger 'Hubble Flow' in those regions of space that could be taken for a dynamical dark energy, or superhorizon effects

  3. Levitating dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Kaloper, Nemanja [Department of Physics, University of California, Davis, CA 95616 (United States); Padilla, Antonio, E-mail: kaloper@physics.ucdavis.edu, E-mail: antonio.padilla@nottingham.ac.uk [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2009-10-01

    A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark U(1)' charge comparable to its mass. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of dark matter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra 'antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic w < −1. They can also lead to a local variation of galaxy-galaxy forces, yielding a larger 'Hubble Flow' in those regions of space that could be taken for a dynamical dark energy, or superhorizon effects.

  4. A hydrodynamic approach to cosmology - Texture-seeded cold dark matter and hot dark matter cosmogonies

    Science.gov (United States)

    Cen, R. Y.; Ostriker, J. P.; Spergel, D. N.; Turok, N.

    1991-01-01

    Hydrodynamical simulations of galaxy formation in a texture-seeded cosmology are presented, with attention given to Omega = 1 galaxies dominated by both hot dark matter (HDM) and cold dark matter (CDM). The simulations include both gravitational and hydrodynamical physics with a detailed treatment of collisional and radiative thermal processes, and use a cooling criterion to estimate galaxy formation. Background radiation fields and Zel'dovich-Sunyaev fluctuations are explicitly computed. The derived galaxy mass function is well fitted by the observed Schechter luminosity function for a baryonic M/L of 3 and total M/L of 60 in galaxies. In both HDM and CDM texture scenarios, the 'galaxies' and 'clusters' are significantly more strongly correlated than the dark matter due to physical bias processes. The slope of the correlation function in both cases is consistent with observations. In contrast to Gaussian models, peaks in the dark matter density distributrion are less correlated than average.

  5. Dark matter superfluid and DBI dark energy

    CERN Document Server

    Cai, Rong-Gen

    2016-01-01

    It was shown recently that, without jeopardizing the success of the $\\Lambda$CDM model on cosmic scales, the MOdified Newtonian Dynamics (MOND) can be derived as an emergent phenomenon when axion-like dark matter particles condense into superfluid on galactic scales. We propose in this letter a Dirac-Born-Infeld (DBI) dark energy conformally coupled to local matter components to solve both galactic and cosmic coincidences that the MOND critical acceleration coincides with present Hubble scale and the matter energy density coincides with dark energy density today. The cosmological evolution of DBI dark energy behaves as a freezing Chaplygin gas and approaches to a cosmological constant in the asymptotic future.

  6. Inflatable Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Davoudiasl, Hooman [Brookhaven National Lab. (BNL), Upton, NY (United States); Hooper, Dan [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); McDermott, Samuel D. [C.N. Yang Inst. for Theoretical Physics, Stony Brook, NY (United States)

    2015-07-30

    We describe a general scenario, dubbed “Inflatable Dark Matter”, in which the density of dark matter particles can be reduced through a short period of late-time inflation in the early universe. The overproduction of dark matter that is predicted within many otherwise well-motivated models of new physics can be elegantly remedied within this context, without the need to tune underlying parameters or to appeal to anthropic considerations. Thermal relics that would otherwise be disfavored can easily be accommodated within this class of scenarios, including dark matter candidates that are very heavy or very light. Furthermore, the non-thermal abundance of GUT or Planck scale axions can be brought to acceptable levels, without invoking anthropic tuning of initial conditions. Additionally, a period of late-time inflation could have occurred over a wide range of scales from ~ MeV to the weak scale or above, and could have been triggered by physics within a hidden sector, with small but not necessarily negligible couplings to the Standard Model.

  7. Dark matter and the LHC

    OpenAIRE

    Bélanger, G.

    2009-01-01

    Cosmological and astrophysical measurements indicate that the universe contains a large amount of dark matter. A number of weak scale dark matter candidates have been proposed in extensions of the standard model. The potential to discover the dark matter particle and determine its properties at the upcoming LHC is summarized.

  8. Axions as Dark Matter Particles

    OpenAIRE

    Duffy, Leanne D.; Bibber, Karl van

    2009-01-01

    We review the current status of axions as dark matter. Motivation, models, constraints and experimental searches are outlined. The axion remains an excellent candidate for the dark matter and future experiments, particularly the Axion Dark Matter eXperiment (ADMX), will cover a large fraction of the axion parameter space.

  9. Tunguska Dark Matter Ball

    CERN Document Server

    Froggatt, C D

    2014-01-01

    It is suggested that the Tunguska event in June 1908 cm-large was due to a cm-large ball of a condensate of bound states of 6 top and 6 anti-top quarks containing highly compressed ordinary matter. Such balls are supposed to make up the dark matter as we earlier proposed. The expected rate of impact of this kind of dark matter ball with the earth seems to crudely match a time scale of 200 years between the impacts. The main explosion of the Tunguska event is explained in our picture as material coming out from deep within the earth, where it has been heated and compressed by the ball penetrating to a depth of several thousand km. Thus the effect has some similarity with volcanic activity as suggested by Kundt. We discuss the possible identification of kimberlite pipes with earlier Tunguska-like events. A discussion of how the dark matter balls may have formed in the early universe is also given.

  10. How clustering dark energy affects matter perturbations

    Science.gov (United States)

    Mehrabi, A.; Basilakos, S.; Pace, F.

    2015-09-01

    The rate of structure formation in the Universe is different in homogeneous and clustered dark energy models. The degree of dark energy clustering depends on the magnitude of its effective sound speed c2_eff and for c2_eff=0 dark energy clusters in a similar fashion to dark matter while for c2_eff=1 it stays (approximately) homogeneous. In this paper we consider two distinct equations of state for the dark energy component, wd = const and w_d=w_0+w_1(z/1+z) with c2_eff as a free parameter and we try to constrain the dark energy effective sound speed using current available data including Type Ia supernovae, baryon acoustic oscillation, cosmic microwave background shift parameter (Planck and WMAP), Hubble parameter, big bang nucleosynthesis and the growth rate of structures fσ8(z). At first we derive the most general form of the equations governing dark matter and dark energy clustering under the assumption that c2_eff=const. Finally, performing an overall likelihood analysis we find that the likelihood function peaks at c2_eff=0; however, the dark energy sound speed is degenerate with respect to the cosmological parameters, namely Ωm and wd.

  11. STRANGE BARYONIC MATTER AND KAON CONDENSATION

    Czech Academy of Sciences Publication Activity Database

    Gazda, Daniel; Friedman, E.; Gal, A.; Mareš, Jiří

    2011-01-01

    Roč. 26, 3-4 (2011), s. 567-569. ISSN 0217-751X. [11th International Workshop on Meson Production, Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/09/1441 Institutional research plan: CEZ:AV0Z10480505 Keywords : (K)over-bar-nuclear bound states * strange baryonic matter * kaon condensation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011

  12. Colloquium: Annual modulation of dark matter

    Science.gov (United States)

    Freese, Katherine; Lisanti, Mariangela; Savage, Christopher

    2013-10-01

    Direct detection experiments, which are designed to detect the scattering of dark matter off nuclei in detectors, are a critical component in the search for the Universe’s missing matter. This Colloquium begins with a review of the physics of direct detection of dark matter, discussing the roles of both the particle physics and astrophysics in the expected signals. The count rate in these experiments should experience an annual modulation due to the relative motion of the Earth around the Sun. This modulation, not present for most known background sources, is critical for solidifying the origin of a potential signal as dark matter. The focus is on the physics of annual modulation, discussing the practical formulas needed to interpret a modulating signal. The dependence of the modulation spectrum on the particle and astrophysics models for the dark matter is illustrated. For standard assumptions, the count rate has a cosine dependence with time, with a maximum in June and a minimum in December. Well-motivated generalizations of these models, however, can affect both the phase and amplitude of the modulation. Shown is how a measurement of an annually modulating signal could teach us about the presence of substructure in the galactic halo or about the interactions between dark and baryonic matter. Although primarily a theoretical review, the current experimental situation for annual modulation and future experimental directions is briefly discussed.

  13. Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data

    Science.gov (United States)

    Väliviita, Jussi; Palmgren, Elina

    2015-07-01

    We employ the Planck 2013 CMB temperature anisotropy and lensing data, and baryon acoustic oscillation (BAO) data to constrain a phenomenological wCDM model, where dark matter and dark energy interact. We assume time-dependent equation of state parameter for dark energy, and treat dark matter and dark energy as fluids whose energy-exchange rate is proportional to the dark-matter density. The CMB data alone leave a strong degeneracy between the interaction rate and the physical CDM density parameter today, ωc, allowing a large interaction rate |Γ| ~ H0. However, as has been known for a while, the BAO data break this degeneracy. Moreover, we exploit the CMB lensing potential likelihood, which probes the matter perturbations at redshift z ~ 2 and is very sensitive to the growth of structure, and hence one of the tools for discerning between the ΛCDM model and its alternatives. However, we find that in the non-phantom models (wde>-1), the constraints remain unchanged by the inclusion of the lensing data and consistent with zero interaction, -0.14 energy transfer from dark energy to dark matter is moderately favoured over the non-interacting model; 0-0.57 < Γ/H0 < -0.1 at 95% CL with CMB+BAO, while addition of the lensing data shifts this to -0.46 < Γ/H0 < -0.01.

  14. Cold and Fuzzy Dark Matter

    OpenAIRE

    Hu, Wayne; Barkana, Rennan; Gruzinov, Andrei

    2000-01-01

    Cold dark matter (CDM) models predict small-scale structure in excess of observations of the cores and abundance of dwarf galaxies. These problems might be solved, and the virtues of CDM models retained, even without postulating {\\it ad hoc} dark matter particle or field interactions, if the dark matter is composed of ultra-light scalar particles (m ~ 10^{-22}eV), initially in a (cold) Bose-Einstein condensate, similar to axion dark matter models. The wave properties of the dark matter stabil...

  15. Monodromy Dark Matter

    CERN Document Server

    Jaeckel, Joerg; Witkowski, Lukas T

    2016-01-01

    Light pseudo-Goldstone bosons such as, e.g. axion-like particles, that are non-thermally produced via the misalignment mechanism are promising dark matter candidates. An important feature of pseudo-Goldstone bosons is their periodic potential, whose scale of periodicity controls all their couplings. As a consequence of the periodicity the maximal potential energy is limited and, hence, producing the observed dark matter density poses significant constraints on the allowed masses and couplings. In the presence of a monodromy, the field range as well as the range of the potential can be significantly extended. As we argue in this paper this has important phenomenological consequences. The constraints on the masses and couplings are ameliorated and couplings to Standard Model particles could be significantly stronger, thereby opening up considerable experimental opportunities. Yet, monodromy models can also give rise to new and qualitatively different features. As a remnant of the periodicity the potential can f...

  16. Annihilating Asymmetric Dark Matter

    CERN Document Server

    Bell, Nicole F; Shoemaker, Ian M

    2014-01-01

    The relic abundance of particle and antiparticle dark matter (DM) need not be vastly different in thermal asymmetric dark matter (ADM) models. By considering the effect of a primordial asymmetry on the thermal Boltzmann evolution of coupled DM and anti-DM, we derive the requisite annihilation cross section. This is used in conjunction with CMB and Fermi-LAT gamma-ray data to impose a limit on the number density of anti-DM particles surviving thermal freeze-out. When the extended gamma-ray emission from the Galactic Center is reanalyzed in a thermal ADM framework, we find that annihilation into $\\tau$ leptons prefer anti-DM number densities 1-4$\\%$ that of DM while the $b$-quark channel prefers 50-100$\\%$.

  17. Co-Decaying Dark Matter

    CERN Document Server

    Dror, Jeff Asaf; Ng, Wee Hao

    2016-01-01

    We propose a new mechanism for thermal dark matter freezeout, termed Co-Decaying Dark Matter. Multi-component dark sectors with degenerate particles and out-of-equilibrium decays can co-decay to obtain the observed relic density. The dark matter density is exponentially depleted through the decay of nearly degenerate particles, rather than from Boltzmann suppression. The relic abundance is set by the dark matter annihilation cross-section, which is predicted to be boosted, and the decay rate of the dark sector particles. The mechanism is viable in a broad range of dark matter parameter space, with a robust prediction of an enhanced indirect detection signal. Finally, we present a simple model that realizes co-decaying dark matter.

  18. An elusive vector dark matter

    Directory of Open Access Journals (Sweden)

    Chuan-Ren Chen

    2015-02-01

    Full Text Available Even though the sensitivity of direct dark matter search experiments reaches the level of about 10−45 cm2, no confident signal of dark matter has been observed. We point out that, if dark matter is a vector boson, the null result in direct dark matter search experiments may be due to the destructive effects in dark-matter–nucleon elastic scattering. We illustrate the scenario using a modified Higgs portal model that includes exotic quarks. The significant cancellation can occur for a certain mass gap between new heavy quark and dark matter. As a result, the spin-independent dark-matter–nucleon elastic scattering is so suppressed that the future direct search experiments will hardly observe the signal of dark matter.

  19. Interacting Dark Matter disguised as Warm Dark Matter

    OpenAIRE

    Boehm, Celine; Riazuelo, Alain; Hansen, Steen H.; Schaeffer, Richard

    2001-01-01

    We explore some of the consequences of Dark Matter-photon interactions on structure formation, focusing on the evolution of cosmological perturbations and performing both an analytical and a numerical study. We compute the cosmic microwave background anisotropies and matter power spectrum in this class of models. We find, as the main result, that when Dark Matter and photons are coupled, Dark Matter perturbations can experience a new damping regime in addition to the usual collisional Silk da...

  20. Levitating Dark Matter

    CERN Document Server

    Kaloper, Nemanja

    2009-01-01

    A sizable fraction of the total energy density of the universe may be in heavy particles with a net dark $U(1)'$ charge equal to its mass, such as the BPS states in string theory. When the charges have the same sign the cancellation between their gravitational and gauge forces may lead to a mismatch between different measures of masses in the universe. Measuring galactic masses by orbits of normal matter, such as galaxy rotation curves or lensing, will give the total mass, while the flows of dark matter agglomerates may yield smaller values if the gauge repulsion is not accounted for. If distant galaxies which house light beacons like SNe Ia contain such dark particles, the observations of their cosmic recession may mistake the weaker forces for an extra `antigravity', and infer an effective dark energy equation of state smaller than the real one. In some cases, including that of a cosmological constant, these effects can mimic $w<-1$. They can also lead to a {\\it local} variation of galaxy-galaxy forces, ...

  1. Observational constraints on variable equation of state parameters of dark matter and dark energy after Planck

    International Nuclear Information System (INIS)

    In this paper, we study a cosmological model in general relativity within the framework of spatially flat Friedmann–Robertson–Walker space–time filled with ordinary matter (baryonic), radiation, dark matter and dark energy, where the latter two components are described by Chevallier–Polarski–Linder equation of state parameters. We utilize the observational data sets from SNLS3, BAO and Planck + WMAP9 + WiggleZ measurements of matter power spectrum to constrain the model parameters. We find that the current observational data offer tight constraints on the equation of state parameter of dark matter. We consider the perturbations and study the behavior of dark matter by observing its effects on CMB and matter power spectra. We find that the current observational data favor the cold dark matter scenario with the cosmological constant type dark energy at the present epoch

  2. Observational constraints on variable equation of state parameters of dark matter and dark energy after Planck

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Suresh, E-mail: sukuyd@gmail.com [Department of Mathematics, BITS Pilani, Pilani Campus, Rajasthan, 333031 (India); Xu, Lixin, E-mail: lxxu@dlut.edu.cn [Institute of Theoretical Physics, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian, 116024 (China)

    2014-10-07

    In this paper, we study a cosmological model in general relativity within the framework of spatially flat Friedmann–Robertson–Walker space–time filled with ordinary matter (baryonic), radiation, dark matter and dark energy, where the latter two components are described by Chevallier–Polarski–Linder equation of state parameters. We utilize the observational data sets from SNLS3, BAO and Planck + WMAP9 + WiggleZ measurements of matter power spectrum to constrain the model parameters. We find that the current observational data offer tight constraints on the equation of state parameter of dark matter. We consider the perturbations and study the behavior of dark matter by observing its effects on CMB and matter power spectra. We find that the current observational data favor the cold dark matter scenario with the cosmological constant type dark energy at the present epoch.

  3. Theory of dark matter superfluidity

    Science.gov (United States)

    Berezhiani, Lasha; Khoury, Justin

    2015-11-01

    We propose a novel theory of dark matter (DM) superfluidity that matches the successes of the Λ cold dark matter (Λ CDM ) model on cosmological scales while simultaneously reproducing the modified Newtonian dynamics (MOND) phenomenology on galactic scales. The DM and MOND components have a common origin, representing different phases of a single underlying substance. DM consists of axionlike particles with mass of order eV and strong self-interactions. The condensate has a polytropic equation of state P ˜ρ3 giving rise to a superfluid core within galaxies. Instead of behaving as individual collisionless particles, the DM superfluid is more aptly described as collective excitations. Superfluid phonons, in particular, are assumed to be governed by a MOND-like effective action and mediate a MONDian acceleration between baryonic matter particles. Our framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not); due to the higher velocity dispersion in clusters, and correspondingly higher temperature, the DM in clusters is either in a mixture of superfluid and the normal phase or fully in the normal phase. The rich and well-studied physics of superfluidity leads to a number of observational signatures: an array of low-density vortices in galaxies; merger dynamics that depend on the infall velocity vs phonon sound speed; distinct mass peaks in bulletlike cluster mergers, corresponding to superfluid and normal components; and interference patters in supercritical mergers. Remarkably, the superfluid phonon effective theory is strikingly similar to that of the unitary Fermi gas, which has attracted much excitement in the cold atom community in recent years. The critical temperature for DM superfluidity is of order mK, comparable to known cold atom Bose-Einstein condensates. Identifying a precise cold atom analog would give important insights on the microphysical interactions underlying DM superfluidity

  4. Weak lensing: Dark Matter, Dark Energy and Dark Gravity

    CERN Document Server

    Heavens, Alan

    2009-01-01

    In this non-specialist review I look at how weak lensing can provide information on the dark sector of the Universe. The review concentrates on what can be learned about Dark Matter, Dark Energy and Dark Gravity, and why. On Dark Matter, results on the confrontation of theoretical profiles with observation are reviewed, and measurements of neutrino masses discussed. On Dark Energy, the interest is whether this could be Einstein's cosmological constant, and prospects for high-precision studies of the equation of state are considered. On Dark Gravity, we consider the exciting prospects for future weak lensing surveys to distinguish General Relativity from extra-dimensional or other gravity theories.

  5. Luminous Dark Matter

    CERN Document Server

    Feldstein, Brian; Rajendran, Surjeet

    2010-01-01

    We propose a dark matter model in which the signal in direct detection experiments arises from electromagnetic, not nuclear, energy deposition. This can provide a novel explanation for DAMA while avoiding many direct detection constraints. The dark matter state is taken nearly degenerate with another state. These states are naturally connected by a dipole moment operator, which can give both the dominant scattering and decay modes between the two states. The signal at DAMA then arises from dark matter scattering in the Earth into the excited state and decaying back to the ground state through emission of a single photon in the detector. This model has unique signatures in direct detection experiments. The density and chemical composition of the detector is irrelevant, only the total volume affects the event rate. In addition, the spectrum is a monoenergetic line, which can fit the DAMA signal well. This model is readily testable at experiments such as CDMS and XENON100 if they analyze their low-energy, electr...

  6. Signals of Supersymmetric Dark Matter

    CERN Document Server

    Abbas, A

    2000-01-01

    The Lightest Supersymmetric Particle predicted in most of the supersymmetric scenarios is an ideal candidate for the dark matter of cosmology. Their detection is of extreme significance today. Recently there have been intriguing signals of a 59 Gev neutralino dark matter at DAMA in Gran Sasso. We look at other possible signatures of dark matter in astrophysical and geological frameworks. The passage of the earth through dense clumps of dark matter would produce large quantities of heat in the interior of this planet through the capture and subsequent annihilation of dark matter particles. This heat would lead to large-scale volcanism which could in turn have caused mass extinctions. The periodicity of such volcanic outbursts agrees with the frequency of palaeontological mass extinctions as well as the observed periodicity in the occurrence of the largest flood basalt provinces on the globe. Binary character of these extinctions is another unique aspect of this signature of dark matter. In addition dark matter...

  7. Coupling dark energy to dark matter perturbations

    CERN Document Server

    Marra, Valerio

    2015-01-01

    This Letter proposes that dark energy in the form of a scalar field could effectively couple to dark matter perturbations. The idea is that dark matter particles could annihilate/interact inside dense clumps and transfer energy to the scalar field, which would then enter an accelerated regime. This hypothesis is interesting as it provides a natural trigger for the onset of the acceleration of the universe, since dark energy starts driving the expansion of the universe when matter perturbations become sufficiently dense. Here we study a possible realization of this general idea by coupling dark energy to dark matter via the linear growth function of matter perturbations. The numerical results show that it is indeed possible to obtain a viable cosmology with the expected series of radiation, matter and dark-energy dominated eras. Moreover, the current density of dark energy is given by the value of the coupling parameters rather than by very special initial conditions for the scalar field. In other words, this ...

  8. Cold dark matter as compact composite objects

    Science.gov (United States)

    Zhitnitsky, Ariel

    2006-08-01

    Dark matter (DM) being the vital ingredient in the cosmos, still remains a mystery. The standard assumption is that the collisionless cold dark matter (CCDM) particles are represented by some weakly interacting fundamental fields which cannot be associated with any standard quarks or leptons. However, recent analyses of structure on galactic and subgalactic scales have suggested discrepancies and stimulated numerous alternative proposals including, e.g. self-interacting dark matter, self-annihilating dark matter, decaying dark matter, to name just a few. We propose the alternative to the standard assumption about the nature of DM particles (which are typically assumed to be weakly interacting fundamental pointlike particles, yet to be discovered). Our proposal is based on the idea that DM particles are strongly interacting composite macroscopically large objects which made of well-known light quarks (or even antiquarks). The required weakness of the DM particle interactions is guaranteed by a small geometrical factor γ˜(area)/(volume)˜B-1/3≪1 of the composite objects with a large baryon charge B≫1, rather than by a weak coupling constant of a new field. We argue that the interaction between hadronic matter and composite dark objects does not spoil the desired properties of the latter as cold matter. We also argue that such a scenario does not contradict to the current observational data. Rather, it has natural explanations of many observed data, such as ΩDM/ΩB˜1 or 511 KeV line from the bulge of our galaxy. We also suggest that composite dark matter may modify the dynamics of structure formation in the central overdense regions of galaxies. We also present a number of other cosmological/astrophysical observations which indirectly support the novel concept of DM nature.

  9. Conformal Gravity: Dark Matter and Dark Energy

    CERN Document Server

    Nesbet, Robert K

    2012-01-01

    This short review examines recent progress in understanding dark matter, dark energy, and galactic halos using theory that departs minimally from standard particle physics and cosmology. Postulated strict conformal symmetry (local Weyl scaling covariance) for all elementary massless fields retains standard theory for fermions and gauge bosons but modifies Einstein-Hilbert general relativity and the Higgs scalar field model, introducing no new physical fields. Subgalactic phenomenology is retained. Without invoking dark matter, conformal gravity and a conformal Higgs model fit empirical data on galactic rotational velocities, galactic halos, and Hubble expansion including dark energy.

  10. Conformal Gravity: Dark Matter and Dark Energy

    Directory of Open Access Journals (Sweden)

    Robert K. Nesbet

    2013-01-01

    Full Text Available This short review examines recent progress in understanding dark matter, dark energy, and galactic halos using theory that departs minimally from standard particle physics and cosmology. Strict conformal symmetry (local Weyl scaling covariance, postulated for all elementary massless fields, retains standard fermion and gauge boson theory but modifies Einstein–Hilbert general relativity and the Higgs scalar field model, with no new physical fields. Subgalactic phenomenology is retained. Without invoking dark matter, conformal gravity and a conformal Higgs model fit empirical data on galactic rotational velocities, galactic halos, and Hubble expansion including dark energy.

  11. Dark Matter Accretion into Supermassive Black Holes

    CERN Document Server

    Peirani, Sébastien

    2008-01-01

    The relativistic accretion rate of dark matter by a black hole is revisited. Under the assumption that the phase space density indicator, $Q=\\rho_{\\infty}/\\sigma^3_{\\infty}$, remains constant during the inflow, the derived accretion rate can be higher up to five orders of magnitude than the classical accretion formula, valid for non-relativistic and non-interacting particles, when typical dark halo conditions are considered. For these typical conditions, the critical point of the flow is located at distances of about 30-150 times the horizon radius. Application of our results to black hole seeds hosted by halos issued from cosmological simulations indicate that dark matter contributes to no more than ~10% of the total accreted mass, confirming that the bolometric quasar luminosity is related to the baryonic accretion history of the black hole.

  12. Dark matter accretion into supermassive black holes

    International Nuclear Information System (INIS)

    The relativistic accretion rate of dark matter by a black hole is revisited. Under the assumption that the phase space density indicator, Q=ρ∞/σ∞3, remains constant during the inflow, the derived accretion rate can be higher up to 5 orders of magnitude than the classical accretion formula, valid for nonrelativistic and noninteracting particles, when typical dark halo conditions are considered. For these typical conditions, the critical point of the flow is located at distances of about 30-150 times the horizon radius. Application of our results to black hole seeds hosted by halos issued from cosmological simulations indicate that dark matter contributes to no more than ∼10% of the total accreted mass, confirming that the bolometric quasar luminosity is related to the baryonic accretion history of the black hole.

  13. Twin Higgs WIMP Dark Matter

    CERN Document Server

    García, Isabel García; March-Russell, John

    2015-01-01

    Dark matter (DM) without a matter asymmetry is studied in the context of Twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) $\\mathbb{Z}_2$ symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realisation of the TH mechanism, the Fraternal Twin Higgs, with only a single generation of twin quarks and leptons, and $SU(3)'\\times SU(2)'$ gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the $\\tau^\\prime$ lepton with a mass $m_{\\tau^\\prime} > m_{\\rm Higgs}/2$, although spin-1 $W^{\\prime\\pm}$ DM and multicomponent DM are also possible (twin baryons are strongly disfavoured by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to th...

  14. Twin Higgs WIMP dark matter

    Science.gov (United States)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-01

    Dark matter (DM) without a matter asymmetry is studied in the context of twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) Z2 symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realization of the TH mechanism, the fraternal twin Higgs, with only a single generation of twin quarks and leptons, and the S U (3 )'×S U (2 )' gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the τ' lepton with a mass mτ'>mHiggs/2 , although spin-1 W'± DM and multicomponent DM are also possible (twin baryons are strongly disfavored by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to the number of relativistic degrees of freedom, Δ Neff . Direct detection signals are below current bounds but accessible in near-future experiments. Indirect detection phenomenology is rich and requires detailed studies of twin hadronization and fragmentation to twin glueballs and quarkonia and their subsequent decay to SM, and possible light twin sector states.

  15. Skew-Flavored Dark Matter

    OpenAIRE

    Agrawal, Prateek; Chacko, Zackaria; Fortes, Elaine C. F. S.; Kilic, Can

    2015-01-01

    We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects Minimal Flavo...

  16. Direct search for dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jonghee; /Fermilab

    2009-12-01

    Dark matter is hypothetical matter which does not interact with electromagnetic radiation. The existence of dark matter is only inferred from gravitational effects of astrophysical observations to explain the missing mass component of the Universe. Weakly Interacting Massive Particles are currently the most popular candidate to explain the missing mass component. I review the current status of experimental searches of dark matter through direct detection using terrestrial detectors.

  17. Dark energy interacting with neutrinos and dark matter: a phenomenological theory

    OpenAIRE

    Kremer, G. M.

    2007-01-01

    A model for a flat homogeneous and isotropic Universe composed of dark energy, dark matter, neutrinos, radiation and baryons is analyzed. The fields of dark matter and neutrinos are supposed to interact with the dark energy. The dark energy is considered to obey either the van der Waals or the Chaplygin equations of state. The ratio between the pressure and the energy density of the neutrinos varies with the red-shift simulating massive and non-relativistic neutrinos at small red-shifts and n...

  18. Couplings between holographic dark energy and dark matter

    OpenAIRE

    Ma, Yin-Zhe; Gong, Yan; Chen, Xuelei

    2009-01-01

    We consider the interaction between dark matter and dark energy in the framework of holographic dark energy, and propose a natural and physically plausible form of interaction, in which the interacting term is proportional to the product of the powers of the dark matter and dark energy densities. We investigate the cosmic evolution in such models. The impact of the coupling on the dark matter and dark energy components may be asymmetric. While the dark energy decouples from the dark matter at...

  19. Singlet fermion dark matter within left-right model

    Science.gov (United States)

    Patra, Sudhanwa; Rao, Soumya

    2016-08-01

    We discuss singlet fermion dark matter within a left-right symmetric model promoting baryon and lepton numbers as separate gauge symmetries. We add a simple Dirac fermionic dark matter singlet under SU(2) L , R with nonzero and equal baryon and lepton number which ensures electric charge neutrality. Such a dark matter candidate interacts with SM particles through the extra ZB,ℓ gauge bosons. This can give rise to a dark matter particle of a few hundred GeV that couples to ∼TeV scale gauge bosons to give the correct relic density. This model thus accommodates TeV scale ZB,ℓ gauge bosons and other low scale BSM particles, which can be easily probed at LHC.

  20. Power spectrum for the Bose-Einstein condensate dark matter

    CERN Document Server

    Velten, Hermano

    2011-01-01

    We assume that dark matter is composed of scalar particles that form a Bose-Einstein condensate (BEC) at some point during the cosmic evolution. Afterwards, cold dark matter is in the form of a condensate and behaves slightly different from the standard dark matter component. We study the large scale perturbative dynamics of the BEC dark matter in a model where this component coexists with baryonic matter and cosmological constant. The perturbative dynamics is studied using neo- Newtonian cosmology (where the pressure is dynamically relevant for the homogeneous and isotropic background) which is assumed to be correct for small values of the sound speed. We show that BEC dark matter effects can be seen in the matter power spectrum if the mass of the condensate particle lies in the range 15meV < m < 700meV leading to a small, but perceptible, excess of power at large scales.

  1. Power spectrum for the Bose-Einstein condensate dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Velten, Hermano, E-mail: velten@physik.uni-bielefeld.de [Departamento de Fisica, UFES, Vitoria, 29075-910 Espirito Santo (Brazil); Fakultaet fuer Physik, Universitaet Bielefeld, Postfach 100131, 33501 Bielefeld (Germany); Wamba, Etienne [Laboratory of Mechanics, Department of Physics, Faculty of Science, University of Yaounde I, P.O. Box 812, Yaounde (Cameroon)

    2012-03-13

    We assume that dark matter is composed of scalar particles that form a Bose-Einstein condensate (BEC) at some point during the cosmic evolution. Afterwards, cold dark matter is in the form of a condensate and behaves slightly different from the standard dark matter component. We study the large scale perturbative dynamics of the BEC dark matter in a model where this component coexists with baryonic matter and cosmological constant. The perturbative dynamics is studied using neo-Newtonian cosmology (where the pressure is dynamically relevant for the homogeneous and isotropic background) which is assumed to be correct for small values of the sound speed. We show that BEC dark matter effects can be seen in the matter power spectrum if the mass of the condensate particle lies in the range 15 MeV

  2. Dark Matter from QCD-balls

    CERN Document Server

    Zhitnitsky, A R

    2003-01-01

    We discuss a novel cold dark matter candidate which is formed from the ordinary quarks during the QCD phase transition when the axion domain wall undergoes an unchecked collapse due to the tension in the wall. If a large number of quarks is trapped inside the bulk of a closed axion domain wall, the collapse stops due to the internal Fermi pressure. In this case the system in the bulk, may reach the critical density when it undergoes a phase transition to a color superconducting phase with the ground state being the quark condensate, similar to BCS theory. If this happens, the new state of matter representing the diquark condensate with a large baryon number B > 10^{20} becomes a stable soliton-like configuration. Consequently, it may serve as a novel cold dark matter candidate. We also discuss a possibility that baryogenesis happens exactly at the same instant during the QCD phase transition.

  3. Dark matter superfluidity and galactic dynamics

    Directory of Open Access Journals (Sweden)

    Lasha Berezhiani

    2016-02-01

    Full Text Available We propose a unified framework that reconciles the stunning success of MOND on galactic scales with the triumph of the ΛCDM model on cosmological scales. This is achieved through the physics of superfluidity. Dark matter consists of self-interacting axion-like particles that thermalize and condense to form a superfluid in galaxies, with ∼mK critical temperature. The superfluid phonons mediate a MOND acceleration on baryonic matter. Our framework naturally distinguishes between galaxies (where MOND is successful and galaxy clusters (where MOND is not: dark matter has a higher temperature in clusters, and hence is in a mixture of superfluid and normal phase. The rich and well-studied physics of superfluidity leads to a number of striking observational signatures.

  4. Dark matter superfluidity and galactic dynamics

    Science.gov (United States)

    Berezhiani, Lasha; Khoury, Justin

    2016-02-01

    We propose a unified framework that reconciles the stunning success of MOND on galactic scales with the triumph of the ΛCDM model on cosmological scales. This is achieved through the physics of superfluidity. Dark matter consists of self-interacting axion-like particles that thermalize and condense to form a superfluid in galaxies, with ∼mK critical temperature. The superfluid phonons mediate a MOND acceleration on baryonic matter. Our framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): dark matter has a higher temperature in clusters, and hence is in a mixture of superfluid and normal phase. The rich and well-studied physics of superfluidity leads to a number of striking observational signatures.

  5. Dark Matter Superfluidity and Galactic Dynamics

    CERN Document Server

    Berezhiani, Lasha

    2015-01-01

    We propose a unified framework that reconciles the stunning success of MOND on galactic scales with the triumph of the LambdaCDM model on cosmological scales. This is achieved through the physics of superfluidity. Dark matter consists of self-interacting axion-like particles that thermalize and condense to form a superfluid in galaxies, with ~mK critical temperature. The superfluid phonons mediate a MOND acceleration on baryonic matter. Our framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): dark matter has a higher temperature in clusters, and hence is in a mixture of superfluid and normal phase. The rich and well-studied physics of superfluidity leads to a number of striking observational signatures.

  6. Baryon Acoustic Oscillation Intensity Mapping of Dark Energy

    Science.gov (United States)

    Chang, Tzu-Ching; Pen, Ue-Li; Peterson, Jeffrey B.; McDonald, Patrick

    2008-03-01

    The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called “dark energy.” To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 109 individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.

  7. Baryon Acoustic Oscillation Intensity Mapping of Dark Energy

    CERN Document Server

    Chang, Tzu-Ching; Peterson, Jeffrey B; McDonald, Patrick

    2007-01-01

    The expansion of the universe appears to be accelerating, and the mysterious anti-gravity agent of this acceleration has been called ``dark energy''. To measure the dynamics of dark energy, Baryon Acoustic Oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 10^9 individual galaxies, by observing the 21cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three dimensional brightness mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.

  8. Baryon acoustic oscillation intensity mapping of dark energy.

    Science.gov (United States)

    Chang, Tzu-Ching; Pen, Ue-Li; Peterson, Jeffrey B; McDonald, Patrick

    2008-03-01

    The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called "dark energy." To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 10(9) individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy. PMID:18352692

  9. Indirect Dark Matter Detection for Flattened Dwarf Galaxies

    OpenAIRE

    Sanders, Jason L.; Evans, N. Wyn; Geringer-Sameth, Alex; Dehnen, Walter

    2016-01-01

    We analyze the effects of flattening on the annihilation (J) and decay (D) factors of dwarf spheroidal galaxies with both analytic and numerical methods. Flattening has two consequences: first, there is a geometric effect as the squeezing (or stretching) of the dark matter distribution enhances (or diminishes) the J-factor; second, the line of sight velocity dispersion of stars must hold up the flattened baryonic component in the flattened dark matter halo. We provide analytic formulae and a ...

  10. The Hubble Web: The Dark Matter Problem and Cosmic Strings

    OpenAIRE

    Alexander, Stephon

    2007-01-01

    I propose a reinterpretation of cosmic dark matter in which a rigid network of cosmic strings formed at the end of inflation. The cosmic strings fulfill three functions: At recombination they provide an accretion mechanism for virializing baryonic and warm dark matter into disks. These cosmic strings survive as configurations which thread spiral and elliptical galaxies leading to the observed flatness of rotation curves and the Tully-Fisher relation. We find a relationship between the rotatio...

  11. Asymmetric Dark Matter Models and the LHC Diphoton Excess

    DEFF Research Database (Denmark)

    Frandsen, Mads T.; Shoemaker, Ian M.

    2016-01-01

    The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. One interpretation of this excess is decays...... have for models of asymmetric DM that attempt to account for the similarity of the dark and visible matter abundances....

  12. Dark matter superfluid and DBI dark energy

    Science.gov (United States)

    Cai, Rong-Gen; Wang, Shao-Jiang

    2016-01-01

    It was shown recently that, without jeopardizing the success of the Λ cold dark matter model on cosmic scales, the modified Newtonian dynamics (MOND) can be derived as an emergent phenomenon when axionlike dark matter particles condense into superfluid on the galactic scales. We propose in this paper a Dirac-Born-Infeld (DBI) scalar field conformally coupled to the matter components. To maintain the success of MOND phenomenon of dark matter superfluid on the galactic scales, the fifth force introduced by the DBI scalar should be screened on the galactic scales. It turns out that the screening effect naturally leads to a simple explanation for a longstanding puzzle that the MOND critical acceleration coincides with present Hubble scale. This galactic coincidence problem is solved, provided that the screened DBI scalar also plays the role of dark energy on the cosmic scales.

  13. Dark Energy, Dark Matter and Gravity

    OpenAIRE

    Bertolami, Orfeu

    2006-01-01

    We discuss the motivation for high accuracy relativistic gravitational experiments in the Solar System and complementary cosmological tests. We focus our attention on the issue of distinguishing a generic scalar-theory of gravity as the underlying physical theory from the usual general relativistic picture, where one expects the presence of fundamental scalar fields associated, for instance, to inflation, dark matter and dark energy.

  14. Dark Matter remains obscure

    CERN Multimedia

    Fabio Capello

    2011-01-01

    It is one of the hidden secrets that literally surround the Universe. Experiments have shown no result so far because trying to capture particles that do not seem to interact with ordinary matter is no trivial exercise. The OSQAR experiment at CERN is dedicated to the search for axions, one of the candidates for Dark Matter. For its difficult challenge, OSQAR counts on one of the world’s most powerful magnets borrowed from the LHC. In a recent publication, the OSQAR collaboration was able to confirm that no axion signal appears out of the background. In other words: the quest is still on.   The OSQAR experiment installed in the SM18 hall. (Photo by F. Capello) The OSQAR “Light Shining Through a Wall” experiment was officially launched in 2007 with the aim of detecting axions, that is, particles that might be the main components of Dark Matter. OSQAR uses the powerful LHC dipole magnet to intensify the predicted photon-axion conversions in the presence of strong m...

  15. Baryogenesis from dark matter in an inflationary universe

    CERN Document Server

    Feng, Wan-Zhe; Nath, Pran

    2013-01-01

    We consider the possibility that in an inflationary universe, the inflaton field decays purely into the dark sector creating asymmetric dark matter at the end of inflation. This asymmetry is subsequently transmuted into leptons and baryons. We consider this possibility in the framework of a generic inflation model, and compute the amount of asymmetric dark matter created from the out of equilibrium decays of the inflaton with CP violating Yukawa couplings. The dark matter asymmetry is then transferred to the visible sector by the asymmetry transfer equation and generates an excess of $B-L$. Baryogenesis occurs via sphaleron processes which conserve $B-L$ but violate $B+L$. A mechanism for the annihilation of the symmetric component of dark matter is also discussed. The model leads to multi-component dark matter consisting of both bosonic and fermionic components.

  16. A dark matter scaling relation from mirror dark matter

    OpenAIRE

    Foot, R.

    2013-01-01

    Mirror dark matter, and other similar dissipative dark matter candidates, need an energy source to stabilize dark matter halos in spiral galaxies. It has been suggested previously that ordinary supernovae can potentially supply the required energy. By matching the energy supplied to the halo from supernovae to that lost due to radiative cooling, we here derive a rough scaling relation, $R_{SN} \\propto \\rho_0 r_0^2$ ($R_{SN}$ is the supernova rate and $\\rho_0, \\ r_0$ the dark matter central de...

  17. Coupling dark energy to dark matter inhomogeneities

    Science.gov (United States)

    Marra, Valerio

    2016-09-01

    We propose that dark energy in the form of a scalar field could effectively couple to dark matter inhomogeneities. Through this coupling energy could be transferred to/from the scalar field, which could possibly enter an accelerated regime. Though phenomenological, this scenario is interesting as it provides a natural trigger for the onset of the acceleration of the universe, since dark energy starts driving the expansion of the universe when matter inhomogeneities become sufficiently strong. Here we study a possible realization of this idea by coupling dark energy to dark matter via the linear growth function of matter perturbations. The numerical results show that it is indeed possible to obtain a viable cosmology with the expected series of radiation, matter and dark-energy dominated eras. In particular, the current density of dark energy is given by the value of the coupling parameters rather than by very special initial conditions for the scalar field. In other words, this model-unlike standard models of cosmic late acceleration-does not suffer from the so-called "coincidence problem" and its related fine tuning of initial conditions.

  18. Plasma dark matter direct detection

    CERN Document Server

    Clarke, Jackson D

    2015-01-01

    Dark matter in spiral galaxies like the Milky Way may take the form of a dark plasma. Hidden sector dark matter charged under an unbroken $U(1)'$ gauge interaction provides a simple and well defined particle physics model realising this possibility. The assumed $U(1)'$ neutrality of the Universe then implies (at least) two oppositely charged dark matter components with self-interactions mediated via a massless "dark photon" (the $U(1)'$ gauge boson). In addition to nuclear recoils such dark matter can give rise to keV electron recoils in direct detection experiments. In this context, the detailed physical properties of the dark matter plasma interacting with the Earth is required. This is a complex system, which is here modelled as a fluid governed by the magnetohydrodynamic equations. These equations are numerically solved for some illustrative examples, and implications for direct detection experiments discussed. In particular, the analysis presented here leaves open the intriguing possibility that the DAMA...

  19. Dark Matter in Many Forms

    OpenAIRE

    Rosner, Jonathan L.

    2005-01-01

    Since ordinary matter constitutes about 4% of the closure density of the Universe while dark matter constitutes about six times as much, it is urged that searches for dark matter consider that it may exist in several forms. Implications for detection and hadron and $e^+ e^-$ colliders are discussed.

  20. Particle Dark Matter Candidates

    CERN Document Server

    Scopel, Stefano

    2007-01-01

    I give a short overview on some of the favorite particle Cold Dark Matter candidates today, focusing on those having detectable interactions: the axion, the KK-photon in Universal Extra Dimensions, the heavy photon in Little Higgs and the neutralino in Supersymmetry. The neutralino is still the most popular, and today is available in different flavours: SUGRA, nuSUGRA, sub-GUT, Mirage mediation, NMSSM, effective MSSM, scenarios with CP violation. Some of these scenarios are already at the level of present sensitivities for direct DM searches.

  1. Dark Matter Velocity Spectroscopy.

    Science.gov (United States)

    Speckhard, Eric G; Ng, Kenny C Y; Beacom, John F; Laha, Ranjan

    2016-01-22

    Dark matter decays or annihilations that produce linelike spectra may be smoking-gun signals. However, even such distinctive signatures can be mimicked by astrophysical or instrumental causes. We show that velocity spectroscopy-the measurement of energy shifts induced by relative motion of source and observer-can separate these three causes with minimal theoretical uncertainties. The principal obstacle has been energy resolution, but upcoming experiments will have the precision needed. As an example, we show that the imminent Astro-H mission can use Milky Way observations to separate possible causes of the 3.5-keV line. We discuss other applications. PMID:26849582

  2. Dark Matter Velocity Spectroscopy

    CERN Document Server

    Speckhard, Eric G; Beacom, John F; Laha, Ranjan

    2016-01-01

    Dark matter decays or annihilations that produce line-like spectra may be smoking-gun signals. However, even such distinctive signatures can be mimicked by astrophysical or instrumental causes. We show that velocity spectroscopy-the measurement of energy shifts induced by relative motion of source and observer-can separate these three causes with minimal theoretical uncertainties. The principal obstacle has been energy resolution, but upcoming and proposed experiments will make significant improvements. As an example, we show that the imminent Astro-H mission can use Milky Way observations to separate possible causes of the 3.5-keV line. We discuss other applications.

  3. Observational constraints on holographic tachyonic dark energy in interaction with dark matter

    CERN Document Server

    Micheletti, Sandro M R

    2009-01-01

    I discuss an interacting tachyonic dark energy model in the context of the holographic principle. The potential of the holographic tachyon field in interaction with dark matter is constructed. The model results are compared with CMB shift parameter, baryonic acoustic oscilations, lookback time and the Constitution supernovae sample. The coupling constant of the model is compatible with zero, but dark energy is not given by a cosmological constant.

  4. Observational constraints on holographic scalar field models of dark energy in interaction with dark matter

    CERN Document Server

    Micheletti, Sandro M R

    2010-01-01

    We discuss two lagrangian interacting dark energy models in the context of the holographic principle. The potentials of the interacting fields are constructed. The models are compared with CMB distance information, baryonic acoustic oscilations, lookback time and the Constitution supernovae sample. The coupling constant of both models considered are different from zero at least with one standard deviation of confidence. Moreover, the sign of coupling, in both cases, are consistent with dark energy decaying into dark matter, alleviating the coincidence problem.

  5. The First Billion Years project: dark matter haloes going from contraction to expansion and back again

    CERN Document Server

    Davis, Andrew J; Vecchia, Claudio Dalla

    2013-01-01

    We study the effect of baryons on the inner dark matter profile in a large statistical sample of the first galaxies using the First Billion Years simulation between $z=16-6$. Using two simulations of the same volume and cosmological initial conditions, one with and one without baryons, we are able to directly compare haloes with their baryon-free counterparts, allowing a detailed study of the modifications to the dark matter density profile due to the presence of baryons. For each of the $\\approx 5000$ haloes in our sample, we quantify the impact of the baryons using $\\eta$, defined as the ratio of dark matter mass enclosed in 100 pc in the baryonic run to its counterpart without baryons. We find there is not one general baryonic impact on the dark matter; many haloes show an enhancement of dark matter in the halo centre compared to the baryon-free simulation, while many others show a deficit. We find that the mean value of $\\eta$ is close to unity, but there is a large dispersion, with a standard deviation o...

  6. Reionization and dark matter decay

    OpenAIRE

    Oldengott, Isabel M.; Boriero, Daniel; Schwarz, Dominik J.

    2016-01-01

    Cosmic reionization and dark matter decay can impact observations of the cosmic microwave sky in a similar way. A simultaneous study of both effects is required to constrain unstable dark matter from cosmic microwave background observations. We compare two reionization models with and without dark matter decay. We find that a reionization model that fits also data from quasars and star forming galaxies results in tighter constraints on the reionization optical depth $\\tau_{\\text{reio}}$, but ...

  7. DARK MATTER SEARCH AT LHC

    CERN Document Server

    Kanaya, N; The ATLAS collaboration

    2013-01-01

    The existence of significant amount of dark matter in the Universe is one of strongest motivations to expect new physics beyond the Standard Model. The observation of dark matter at the LHC is a grand challenge next to the discovery of the Higgs boson. Following sections present latest LHC results on the search for dark matter in various final states with large missing transverse energy using data collected in 2011 and 2012.

  8. Dark matter searches with CMS

    CERN Document Server

    Jeitler, Manfred

    2016-01-01

    The existence of dark matter, indicated by astronomical observations, is one of the main proofs of physics beyond the standard model. Despite its abundance, dark matter has not been directly observed yet. This talk presents several searches for dark matter production in proton-proton collisions at 7, 8, and 13 TeV at the LHC, performed by the CMS collaboration. They are interpreted in terms of simplified models with different structures and mediators, as well as generic effective theory terms.

  9. Collisional versus Collisionless Dark Matter

    OpenAIRE

    Moore, Ben; Gelato, Sergio; Jenkins, Adrian; Pearce, F. R.; Quilis, Vicent

    2000-01-01

    We compare the structure and substructure of dark matter halos in model universes dominated by collisional, strongly self interacting dark matter (SIDM) and collisionless, weakly interacting dark matter (CDM). While SIDM virialised halos are more nearly spherical than CDM halos, they can be rotationally flattened by as much as 20% in their inner regions. Substructure halos suffer ram-pressure truncation and drag which are more rapid and severe than their gravitational counterparts tidal strip...

  10. Dark matter. A light move

    Energy Technology Data Exchange (ETDEWEB)

    Redondo, Javier [Muenchen Univ. (Germany). Arnold Sommerfeld Center; Max-Planck-Institut fuer Physik, Muenchen (Germany); Doebrich, Babette [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-11-15

    This proceedings contribution reports from the workshop Dark Matter - a light move, held at DESY in Hamburg in June 2013. Dark Matter particle candidates span a huge parameter range. In particular, well motivated candidates exist also in the sub-eV mass region, for example the axion. Whilst a plethora of searches for rather heavy Dark Matter particles exists, there are only very few experiments aimed at direct detection of sub-eV Dark Matter to this date. The aim of our workshop was to discuss if and how this could be changed in the near future.

  11. Dark Matter and Dark Energy Explained

    Science.gov (United States)

    Aisenberg, Sol

    2006-03-01

    The standard model of the universe has many mysteries and defects requiring the use of large fudge factors such as Dark Matter and Dark Energy. We will show that Dark Matter is needed when we try to extend Newton's law of gravity (based upon observations in our solar system) to galactic distances. Dark Matter was introduced to explain the observed flat velocity rotation curves of the outer parts of spiral galaxies, as observed by Vera. Rubin. Much earlier, the (under appreciated) Fritz Zwicky introduced the need for large amounts of missing invisible matter to explain the surprising observed motion of groups of remote galaxies. In our hypothesis, the modification of Newton's laws by the addition of a linear term to the gravitational constant that increases with distance will eliminate the need for dark matter. Our hypothesis is different from the MOND theory of Milgrom, which depends upon acceleration. The Red shift observations by Hubble as a function of distance, and interpreted as ``apparent Doppler effect'' led to the unproven belief that the universe is expanding, and thus to the Big Bang. In turn the apparent acceleration of the expansion required the introduction of Dark Energy. Actually there are three additional components of the red shift that are solely due to gravity and distance and can be larger than the Doppler contribution.

  12. Dark matter, shared asymmetries, and galactic gamma ray signals

    Science.gov (United States)

    Fonseca, Nayara; Necib, Lina; Thaler, Jesse

    2016-02-01

    We introduce a novel dark matter scenario where the visible sector and the dark sector share a common asymmetry. The two sectors are connected through an unstable mediator with baryon number one, allowing the standard model baryon asymmetry to be shared with dark matter via semi-annihilation. The present-day abundance of dark matter is then set by thermal freeze-out of this semi-annihilation process, yielding an asymmetric version of the WIMP miracle as well as promising signals for indirect detection experiments. As a proof of concept, we find a viable region of parameter space consistent with the observed Fermi excess of GeV gamma rays from the galactic center.

  13. Dark Matter, Shared Asymmetries, and Galactic Gamma Ray Signals

    CERN Document Server

    Fonseca, Nayara; Thaler, Jesse

    2015-01-01

    We introduce a novel dark matter scenario where the visible sector and the dark sector share a common asymmetry. The two sectors are connected through an unstable mediator with baryon number one, allowing the standard model baryon asymmetry to be shared with dark matter via semi-annihilation. The present-day abundance of dark matter is then set by thermal freeze-out of this semi-annihilation process, yielding an asymmetric version of the WIMP miracle as well as promising signals for indirect detection experiments. As a proof of concept, we find a viable region of parameter space consistent with the observed Fermi excess of GeV gamma rays from the galactic center.

  14. Pionic dark matter

    International Nuclear Information System (INIS)

    We study a phenomenological model where the lightest dark matter (DM) particles are the pseudo-Goldstone excitations associated with a spontaneously broken symmetry, and transforming linearly with respect to an unbroken group HDM. For definiteness we take HDM=SU(N) and assume the Goldstone particles are bosons; in parallel with QCD, we refer to these particles as dark-matter pions. This scenario is in contrast to the common assumption that DM fields transform linearly under the full symmetry of the model. We illustrate the formalism by treating in detail the case of HDM=SU(2), in particular we calculate all the interactions relevant for the Boltzmann equations, which we solve numerically; we also derive approximate analytic solutions and show their consistency with the numerical results. We then compare the results with the constraints derived from the cold DM and direct detection experiments and derive the corresponding restrictions on the model parameters. We also briefly comment on constraints from indirect detection of DM

  15. Matter-antimatter asymmetry and dark matter from torsion

    Science.gov (United States)

    Popławski, Nikodem J.

    2011-04-01

    We propose a simple scenario which explains the observed matter-antimatter imbalance and the origin of dark matter in the Universe. We use the Einstein-Cartan-Sciama-Kibble theory of gravity which naturally extends general relativity to include the intrinsic spin of matter. Spacetime torsion produced by spin generates, in the classical Dirac equation, the Hehl-Datta term which is cubic in spinor fields. We show that under a charge-conjugation transformation this term changes sign relative to the mass term. A classical Dirac spinor and its charge conjugate therefore satisfy different field equations. Fermions in the presence of torsion have higher energy levels than antifermions, which leads to their decay asymmetry. Such a difference is significant only at extremely high densities that existed in the very early Universe. We propose that this difference caused a mechanism, according to which heavy fermions existing in such a Universe and carrying the baryon number decayed mostly to normal matter, whereas their antiparticles decayed mostly to hidden antimatter which forms dark matter. The conserved total baryon number of the Universe remained zero.

  16. Open cold dark matter models

    CERN Document Server

    Liddle, A R; Roberts, D; Viana, P T P; Liddle, Andrew R; Lyth, David H; Roberts, David; Viana, Pedro P T

    1995-01-01

    Motivated by recent developments in inflationary cosmology indicating the possibility of obtaining genuinely open universes in some models, we compare the predictions of Cold Dark Matter models in open universes with a variety of observational information. We allow arbitrary variation of the density parameter \\Omega_0 and the Hubble parameter h, and take full account of the baryon content assuming standard nucleosynthesis. We normalize the power spectrum using the recent analysis of the two year COBE DMR data by Gorski et al. (1995). We then consider a variety of observations, namely the galaxy correlation function, bulk flows, the abundance of galaxy clusters and the abundance of damped Lyman alpha systems. For the last two of these, we provide a new treatment appropriate to open universes. We find that if one allows an arbitrary h, then a good fit is available for any \\Omega_0 greater than 0.35, though for \\Omega_0 close to one the required h is alarmingly low. Models with \\Omega_0 0.6, as favoured by rece...

  17. Matter, dark matter, and anti-matter in search of the hidden universe

    CERN Document Server

    Mazure, Alain

    2012-01-01

    For over ten years, the dark side of the universe has been headline news. Detailed studies of the rotation of spiral galaxies, and 'mirages' created by clusters of galaxies bending the light from very remote objects, have convinced astronomers of the presence of large quantities of dark (unseen) matter in the cosmos. Moreover, in the 1990s, it was discovered that some four to five billion years ago the expansion of the universe entered a phase of acceleration. This implies the existence of dark energy. The nature of these 'dark; ingredients remains a mystery, but they seem to comprise about 95 percent of the matter/energy content of the universe. As for ordinary matter, although we are immersed in a sea of dark particles, including primordial neutrinos and photons from 'fossil' cosmological radiation, both we and our environment are made of ordinary, baryonic matter. Strangely, even if 15-20 percent of matter is baryonic matter, this represents only 4-5 percent of the total matter/energy content of the cosmos...

  18. Lectures on Dark Matter Physics

    OpenAIRE

    Lisanti, Mariangela

    2016-01-01

    Rotation curve measurements from the 1970s provided the first strong indication that a significant fraction of matter in the Universe is non-baryonic. In the intervening years, a tremendous amount of progress has been made on both the theoretical and experimental fronts in the search for this missing matter, which we now know constitutes nearly 85% of the Universe's matter density. These series of lectures, first given at the TASI 2015 summer school, provide an introduction to the basics of d...

  19. ZEPLIN-III direct dark matter search : final results and measurements in support of next generation instruments

    OpenAIRE

    Reichhart, Lea

    2013-01-01

    Astrophysical observations give convincing evidence for a vast non-baryonic component, the so-called dark matter, accounting for over 20% of the overall content of our Universe. Direct dark matter search experiments explore the possibility of interactions of these dark matter particles with ordinary baryonic matter via elastic scattering resulting in single nuclear recoils. The ZEPLIN-III detector operated on the basis of a dualphase (liquid/gas) xenon target, recording events ...

  20. Quantum vacuum and dark matter

    Science.gov (United States)

    Hajdukovic, Dragan Slavkov

    2012-01-01

    Recently, the gravitational polarization of the quantum vacuum was proposed as alternative to the dark matter paradigm. In the present paper we consider four benchmark measurements: the universality of the central surface density of galaxy dark matter haloes, the cored dark matter haloes in dwarf spheroidal galaxies, the non-existence of dark disks in spiral galaxies and distribution of dark matter after collision of clusters of galaxies (the Bullet cluster is a famous example). Only some of these phenomena (but not all of them) can (in principle) be explained by the dark matter and the theories of modified gravity. However, we argue that the framework of the gravitational polarization of the quantum vacuum allows the understanding of the totality of these phenomena.

  1. Understanding the Fundamental Properties of Dark Matter & Dark Energy in Structure formation and Cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Richard, S.

    2008-02-01

    This program is concerned with developing and verifying the validityof observational methods for constraining the properties of dark matter and dark energy in the universe. Excellent progress has been made in comparing observational projects involving weak gravitational lensing using both ground and space-based instruments, in further constraining the nature of dark matter via precise measures of its distribution in clusters of galaxies using strong gravitational lensing, in demonstrating the possible limitations of using distant supernovae in future dark energy missions, and in investigating the requirement for ground-based surveys of baryonic acoustic oscillations.

  2. Gravitational Origin of Dark Matter

    CERN Document Server

    Babichev, Eugeny; Raidal, Martti; Schmidt-May, Angnis; Urban, Federico; Veermäe, Hardi; von Strauss, Mikael

    2016-01-01

    Observational evidence for the existence of Dark Matter is limited to its gravitational effects. The extensive program for dedicated searches has yielded null results so far, challenging the most popular models. Here we propose that this is the case because the very existence of cold Dark Matter is a manifestation of gravity itself. The consistent bimetric theory of gravity, the only known ghost-free extension of General Relativity involving a massless and a massive spin-2 field, automatically contains a perfect Dark Matter candidate. We demonstrate that the massive spin-2 particle can be heavy, stable on cosmological scales, and that it interacts with matter only through a gravitational type of coupling. Remarkably, these features persist in the same region of parameter space where bimetric theory satisfies the current gravity tests. We show that the observed Dark Matter abundance can be generated via freeze-in and suggest possible particle physics and gravitational signatures of our bimetric Dark Matter mod...

  3. Skew-Flavored Dark Matter

    CERN Document Server

    Agrawal, Prateek; Fortes, Elaine C F S; Kilic, Can

    2015-01-01

    We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects Minimal Flavor Violation, and is therefore naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in which dark matter couples to right-handed charged leptons. In large regions of parameter space the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. These events exhibit a characteristic flavor pattern that may allow this cla...

  4. Candidates and prospects of detection for particle dark matter

    International Nuclear Information System (INIS)

    The mystery of what makes up the non-baryonic mass in the universe has deepened. Cosmological measurements tell us with high significance that baryons only make up 4 to 5 percent of critical density, whereas CMB and other measurements point to a total relative matter density of around 30 percent. Although the simplest possibilities like massive neutrinos are ruled out as the main component of dark matter, there are several other, belonging to extensions of the Standard Model which are becoming more and more plausible. Supersymmetric particles are among these favoured candidates, but there are also others based on extra dimensions and other current theoretical ideas. The hunt for dark matter will intensify in the coming years with a large set of accelerator, direct detection and indirect detection experiments each having a fair chance of making the first detection. The talk will cover some of the different particle dark matter candidates and their detection properties. (author)

  5. Interacting Dark Matter and Dark Energy

    CERN Document Server

    Farrar, G R; Farrar, Glennys R.

    2004-01-01

    We discuss models for the cosmological dark sector in which the energy density of a scalar field approximates Einstein's cosmological constant and the scalar field value determines the dark matter particle mass by a Yukawa coupling. A model with one dark matter family can be adjusted so the observational constraints on the cosmological parameters are close to but different from what is predicted by the Lambda CDM model. This may be a useful aid to judging how tightly the cosmological parameters are constrained by the new generation of cosmological tests that depend on the theory of structure formation. In a model with two families of dark matter particles the scalar field may be locked to near zero mass for one family. This can suppress the long-range scalar force in the dark sector and eliminate evolution of the effective cosmological constant and the mass of the nonrelativistic dark matter particles, making the model close to Lambda CDM, until the particle number density becomes low enough to allow the scal...

  6. Split neutrinos - leptogenesis, dark matter and inflation

    CERN Document Server

    Mazumdar, Anupam

    2012-01-01

    We propose a simple framework to split neutrinos with a slight departure from tribimaximal mixing - where two of the neutrinos are Majorana type which provide thermal leptogenesis. The Dirac neutrino with a tiny Yukawa coupling explains primordial inflation and the cosmic microwave background radiation, where the inflaton is the gauge invariant flat direction. The observed baryon asymmetry, and the scale of inflation are intimately tied to the observed reactor angle, which can be further constrained by the LHC and the neutrinoless double beta decay experiments. The model also provides the lightest right handed sneutrino as a part of the inflaton to be the dark matter candidate.

  7. Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data

    CERN Document Server

    Valiviita, Jussi

    2015-01-01

    We employ the Planck 2013 CMB temperature anisotropy and lensing data, and baryon acoustic oscillation (BAO) data to constrain a phenomenological $w$CDM model, where dark matter and dark energy interact. We assume time-dependent equation of state parameter for dark energy, and treat dark matter and dark energy as fluids whose energy-exchange rate is proportional to the dark-matter density. The CMB data alone leave a strong degeneracy between the interaction rate and the physical CDM density parameter today, $\\omega_c$, allowing a large interaction rate $|\\Gamma| \\sim H_0$. However, as has been known for a while, the BAO data break this degeneracy. Moreover, we exploit the CMB lensing potential likelihood, which probes the matter perturbations at redshift $z \\sim 2$ and is very sensitive to the growth of structure, and hence one of the tools for discerning between the $\\Lambda$CDM model and its alternatives. However, we find that in the non-phantom models ($w_{\\mathrm{de}}>-1$), the constraints remain unchange...

  8. Search for pseudoscalar cold dark matter

    Energy Technology Data Exchange (ETDEWEB)

    van Bibber, K.; Stoeffl, W.; LLNL Collaborators

    1992-05-29

    AH dynamical evidence points to the conclusion that the predominant form of matter in the universe is in a non-luminous form. Furthermore, large scale deviations from uniform Hubble flow, and the recent COBE reports of inhomogeneities in the cosmic microwave background strongly suggest that we live in an exactly closed universe. If this is true, then ordinary baryonic matter could only be a minority component (10% at most) of the missing mass, and that what constitutes the majority of the dark matter must involve new physics. The axion is one of very few well motivated candidates which may comprise the dark matter. Additionally it is a `cold` dark-matter candidate which is preferred by the COBE data. We propose to construct and operate an experiment to search for axions which may constitute the dark matter of our own galaxy. As proposed by Sikivie, dark-matter axions may be detected by their stimulated conversion into monochromatic microwave photons in a tunable high-Q cavity inside a strong magnetic field. Our ability to mount an experiment quickly and take data within one year is due to a confluence of three factors. The first is the availability of a compact high field superconducting magnet and a local industrial partner, Wang NMR, who can make a very thermally efficient and economical cryostat for it. The second is an ongoing joint venture with the Institute for Nuclear Research of the Russian Academy of Sciences to do R&D on metalized precision-formed ceramic microwave cavities for the axion search, and INR has commited to providing all the microwave cavity arrays for this experiment, should this proposal be approved. The third is a commitment of very substantial startup capital monies from MIT for all of the state-of-the-art ultra-low noise microwave electronics, to one of our outstanding young collaborators who is joining their faculty.

  9. Dark Energy Scaling from Dark Matter to Acceleration

    OpenAIRE

    Bielefeld, Jannis; Caldwell, Robert R.; Linder, Eric V.

    2014-01-01

    The dark sector of the Universe need not be completely separable into distinct dark matter and dark energy components. We consider a model of early dark energy in which the dark energy mimics a dark matter component in both evolution and perturbations at early times. Barotropic aether dark energy scales as a fixed fraction, possibly greater than one, of the dark matter density and has vanishing sound speed at early times before undergoing a transition. This gives signatures not only in cosmic...

  10. Antideuterons from supersymmetric dark matter

    CERN Document Server

    Donato, F; Maurin, D

    2007-01-01

    We calculate the antideuteron flux expected from dark matter annihilation in the galactic halo. The propagation is treated in a full 2-D propagation model consistent with the results obtained from the propagation of B/C and other galactic species. We discuss the potentials of this indirect dark matter detection means, with special emphasis on the possible sources of uncertainties affecting future measurements

  11. Dark matter searches at ATLAS

    CERN Document Server

    Gramling, Johanna; The ATLAS collaboration

    2016-01-01

    Compelling astrophysical evidence for dark matter makes it important and interesting to look for signatures of missing energies at the LHC. This talk presents the different searches carried out with the ATLAS detector at the LHC, and there results and interpretations in the context of dark matter production.

  12. ℤ2 SIMP dark matter

    International Nuclear Information System (INIS)

    Dark matter with strong self-interactions provides a compelling solution to several small-scale structure puzzles. Under the assumption that the coupling between dark matter and the Standard Model particles is suppressed, such strongly interacting massive particles (SIMPs) allow for a successful thermal freeze-out through N-to-N′ processes, where N dark matter particles annihilate to N′ of them. In the most common scenarios, where dark matter stability is guaranteed by a ℤ2 symmetry, the seemingly leading annihilating channel, i.e. 3-to-2 process, is forbidden, so the 4-to-2 one dominate the production of the dark matter relic density. Moreover, cosmological observations require that the dark matter sector is colder than the thermal bath of Standard Model particles, a condition that can be dynamically generated via a small portal between dark matter and Standard Model particles, à la freeze-in. This scenario is exemplified in the context of the Singlet Scalar dark matter model

  13. The Hunt for Dark Matter

    Science.gov (United States)

    Gelmini, Graciela B.

    These lectures, given at the 2014 Theoretical Advanced Study Institute (TASI), are an introduction to what we know at present about dark matter and the major current experimental and observational efforts to identify what it consists of. They attempt to present the complexities of the subject, making clear common simplifying assumptions, to better understand the reach of dark matter searches.

  14. Bright galaxies, dark matters.

    Science.gov (United States)

    Rubin, V.

    This book charts two extraordinary journeys: the road to a better understanding of the structure and composition of the universe, and V. Rubin's own pathbreaking career. The scientific papers included here offer an overview of the topic that has been the major focus of her career: the motions of stars within galaxies and the evidence from these motions that most of the matter in the universe is dark. Elsewhere the author examines some of the tools of her trade - from star charts to the Hubble Telescope to some of the observatories where she has worked. The concluding section, "The astronomical life", finds V. Rubin writing candidly about the demands and rewards of her career, offering insightful portraits of colleagues, friends, and other notable women in science.

  15. Repulsive Dark Matter

    CERN Document Server

    Goodman, J

    2000-01-01

    It seems necessary to suppress, at least partially, the formation ofstructure on subgalactic scales. As an alternative to warm or collisional darkmatter, I postulate a condensate of massive bosons interacting via a repulsiveinterparticle potential, plus gravity. This leads to a minimum lengthscale forbound objects, and to superfluidity. Galactic dynamics may differ significantlyfrom that of more generic dark matter in not unwelcome ways, especially in thecore. Such particles can be realized as quanta of a relativistic massive scalarfield with a quartic self-interaction. At high densities, the equation of statehas the same form as that of an ideal relativistic gas despite theinteractions. If the nonrelativistic lengthscale is of order a kiloparsec, thenthe energy density in these particles was comparable to that of photons atearly times, but small enough to avoid conflict with primordialnucleosynthesis.

  16. Ultralight particle dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Ringwald, A.

    2013-10-15

    We review the physics case for very weakly coupled ultralight particles beyond the Standard Model, in particular for axions and axion-like particles (ALPs): (i) the axionic solution of the strong CP problem and its embedding in well motivated extensions of the Standard Model; (ii) the possibility that the cold dark matter in the Universe is comprised of axions and ALPs; (iii) the ALP explanation of the anomalous transparency of the Universe for TeV photons; and (iv) the axion or ALP explanation of the anomalous energy loss of white dwarfs. Moreover, we present an overview of ongoing and near-future laboratory experiments searching for axions and ALPs: haloscopes, helioscopes, and light-shining-through-a-wall experiments.

  17. Conformal Gravity: Dark Matter and Dark Energy

    OpenAIRE

    Nesbet, Robert K.

    2013-01-01

    This short review examines recent progress in understanding dark matter, dark energy, and galactic halos using theory that departs minimally from standard particle physics and cosmology. Strict conformal symmetry (local Weyl scaling covariance), postulated for all elementary massless fields, retains standard fermion and gauge boson theory but modifies Einstein–Hilbert general relativity and the Higgs scalar field model, with no new physical fields. Subgalactic phenomenology is retai...

  18. Scattering of Dark Matter and Dark Energy

    OpenAIRE

    Simpson, Fergus

    2010-01-01

    We demonstrate how the two dominant constituents of the Universe, dark energy and dark matter, could possess a large scattering cross-section without considerably impacting observations. Unlike models involving energy exchange between the two fluids, the background cosmology remains unaltered, leaving fewer observational signatures. Following a brief review of the scattering cross-sections between cosmologically significant particles, we explore the implications of an elastic interaction betw...

  19. The challenge of dark matter

    International Nuclear Information System (INIS)

    This presentation makes a review of our knowledge about dark matter and about its constraints for cosmology. Dark matter most likely is a weakly interacting (massive?) particle like Wimp or LSP motivated by theory of supersymmetry. Astrophysical probes of dark matter complement collider experiments in the hunt for Wimps and non-Wimps. Two ways of detection: Direct detection - many Wimps pass through us every second and about ten million Wimps per m2.s pass through the earth; Indirect detection - halo Wimps occasionally annihilate today into energetic particles (τ, γ, p-bar, e+). Indirect detection can be done by: using the sun as a dark matter trap, using the Fermi satellite for detecting the annihilation of γ-rays from the Galactic centre, using antiprotons, or using positron fraction. In conclusion, dark matter detection is essential for credibility and only indirect detection in multiple windows will demonstrate its cosmological significance

  20. The challenge of dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Silk, Joe [Oxford Astrophysics, Department of Physics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH (United Kingdom)

    2010-07-01

    This presentation makes a review of our knowledge about dark matter and about its constraints for cosmology. Dark matter most likely is a weakly interacting (massive?) particle like Wimp or LSP motivated by theory of supersymmetry. Astrophysical probes of dark matter complement collider experiments in the hunt for Wimps and non-Wimps. Two ways of detection: Direct detection - many Wimps pass through us every second and about ten million Wimps per m{sup 2}.s pass through the earth; Indirect detection - halo Wimps occasionally annihilate today into energetic particles ({tau}, {gamma}, p-bar, e{sup +}). Indirect detection can be done by: using the sun as a dark matter trap, using the Fermi satellite for detecting the annihilation of {gamma}-rays from the Galactic centre, using antiprotons, or using positron fraction. In conclusion, dark matter detection is essential for credibility and only indirect detection in multiple windows will demonstrate its cosmological significance

  1. In search of dark matter

    CERN Document Server

    Freeman, Kenneth C

    2006-01-01

    The dark matter problem is one of the most fundamental and profoundly difficult to solve problems in the history of science. Not knowing what makes up most of the known universe goes to the heart of our understanding of the Universe and our place in it. In Search of Dark Matter is the story of the emergence of the dark matter problem, from the initial erroneous ‘discovery’ of dark matter by Jan Oort to contemporary explanations for the nature of dark matter and its role in the origin and evolution of the Universe. Written for the educated non-scientist and scientist alike, it spans a variety of scientific disciplines, from observational astronomy to particle physics. Concepts that the reader will encounter along the way are at the cutting edge of scientific research. However the themes are explained in such a way that no prior understanding of science beyond a high school education is necessary.

  2. Bimetric gravity and dark matter

    CERN Document Server

    Bernard, Laura; Heisenberg, Lavinia

    2015-01-01

    We review some recent proposals for relativistic models of dark matter in the context of bimetric gravity. The aim is to solve the problems of cold dark matter (CDM) at galactic scales, and to reproduce the phenomenology of the modified Newtonian dynamics (MOND), while still being in agreement with the standard cosmological model $\\Lambda$-CDM at large scales. In this context a promising alternative is dipolar dark matter (DDM) in which two different species of dark matter particles are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. The phenomenology of MOND then results from a mechanism of gravitational polarization. Probably the best formulation of the model is within the framework of recently developed massive bigravity theories. Then the gravitational sector of the model is safe by construction, but a ghostly degree of freedom in the decoupling limit is still present in the dark matter sector. Future work should analyse the cosmological solutions of...

  3. Phases of Cannibal Dark Matter

    CERN Document Server

    Farina, Marco; Ruderman, Joshua T; Trevisan, Gabriele

    2016-01-01

    A hidden sector with a mass gap undergoes an epoch of cannibalism if number changing interactions are active when the temperature drops below the mass of the lightest hidden particle. During cannibalism, the hidden sector temperature decreases only logarithmically with the scale factor. We consider the possibility that dark matter resides in a hidden sector that underwent cannibalism, and has relic density set by the freeze-out of two-to-two annihilations. We identify three novel phases, depending on the behavior of the hidden sector when dark matter freezes out. During the cannibal phase, dark matter annihilations decouple while the hidden sector is cannibalizing. During the chemical phase, only two-to-two interactions are active and the total number of hidden particles is conserved. During the one way phase, the dark matter annihilation products decay out of equilibrium, suppressing the production of dark matter from inverse annihilations. We map out the distinct phenomenology of each phase, which includes ...

  4. Constraints on the coupling between dark energy and dark matter from CMB data

    Science.gov (United States)

    Murgia, R.; Gariazzo, S.; Fornengo, N.

    2016-04-01

    We investigate a phenomenological non-gravitational coupling between dark energy and dark matter, where the interaction in the dark sector is parameterized as an energy transfer either from dark matter to dark energy or the opposite. The models are constrained by a whole host of updated cosmological data: cosmic microwave background temperature anisotropies and polarization, high-redshift supernovae, baryon acoustic oscillations, redshift space distortions and gravitational lensing. Both models are found to be compatible with all cosmological observables, but in the case where dark matter decays into dark energy, the tension with the independent determinations of H0 and σ8, already present for standard cosmology, increases: this model in fact predicts lower H0 and higher σ8, mostly as a consequence of the higher amount of dark matter at early times, leading to a stronger clustering during the evolution. Instead, when dark matter is fed by dark energy, the reconstructed values of H0 and σ8 nicely agree with their local determinations, with a full reconciliation between high- and low-redshift observations. A non-zero coupling between dark energy and dark matter, with an energy flow from the former to the latter, appears therefore to be in better agreement with cosmological data.

  5. Supersymmetric Partially Interacting Dark Matter

    OpenAIRE

    Fischler, Willy; Lorshbough, Dustin; Tangarife, Walter

    2014-01-01

    We present a model of partially interacting dark matter (PIDM) within the framework of supersymmetry with gauge mediated symmetry breaking. Dark sector atoms are produced through Affleck-Dine baryogenesis in the dark sector while avoiding the production of Q-ball relics. We discuss the astrophysical constraints relevant for this model and the possibility of dark galactic disk formation. In addition, jet emission from rotating black holes is discussed in the context of this class of models.

  6. Interacting dark energy collapse with matter components separation

    Energy Technology Data Exchange (ETDEWEB)

    Delliou, M. Le [Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66.318 — 05314-970, São Paulo, SP (Brazil); Barreiro, T., E-mail: delliou@cii.fc.ul.pt, E-mail: tmbarreiro@ulusofona.pt [Departamento de Matemática da FFMCC, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 376 — 1749-024 Lisboa (Portugal)

    2013-02-01

    We use the spherical collapse model of structure formation to investigate the separation in the collapse of uncoupled matter (essentially baryons) and coupled dark matter in an interacting dark energy scenario. Following the usual assumption of a single radius of collapse for all species, we show that we only need to evolve the uncoupled matter sector to obtain the evolution for all matter components. This gives us more information on the collapse with a simplified set of evolution equations compared with the usual approaches. We then apply these results to four quintessence potentials and show how we can discriminate between different quintessence models.

  7. Solving the Dark Matter Problem

    International Nuclear Information System (INIS)

    Cosmological observations have firmly established that the majority of matter in the universe is of an unknown type, called 'dark matter'. A compelling hypothesis is that the dark matter consists of weakly interacting massive particles (WIMPs) in the mass range around 100 GeV. If the WIMP hypothesis is correct, such particles could be created and studied at accelerators. Furthermore they could be directly detected as the primary component of our galaxy. Solving the dark matter problem requires that the connection be made between the two. We describe some theoretical and experimental avenues that might lead to this connection.

  8. Dark matter, dark energy and gravity

    Science.gov (United States)

    Robson, B. A.

    2015-02-01

    Within the framework of the Generation Model (GM) of particle physics, gravity is identified with the very weak, universal and attractive residual color interactions acting between the colorless particles of ordinary matter (electrons, neutrons and protons), which are composite structures. This gravitational interaction is mediated by massless vector bosons (hypergluons), which self-interact so that the interaction has two additional features not present in Newtonian gravitation: (i) asymptotic freedom and (ii) color confinement. These two additional properties of the gravitational interaction negate the need for the notions of both dark matter and dark energy.

  9. Unravelling the Dark Matter - Dark Energy Paradigm

    OpenAIRE

    Cahill, Reginald T.

    2009-01-01

    The standard LambdaCDM model of cosmology is usually understood to arise from demanding that the Friedmann-Lemaitre-Robertson-Walker (FLRW) metric satisfy the General Relativity dynamics for spacetime metrics. The FLRW data-based dominant parameter values, Omega_Lambda=0.73 and Omega_m=0.27 for the dark energy and dark matter+matter, respectively, are then determined by fitting the supernova red-shift data. However in the pressure-less flat-space case the LambdaCDM model is most easily derive...

  10. Dark matter, dark energy and gravity

    International Nuclear Information System (INIS)

    Within the framework of the Generation Model (GM) of particle physics, gravity is identified with the very weak, universal and attractive residual color interactions acting between the colorless particles of ordinary matter (electrons, neutrons and protons), which are composite structures. This gravitational interaction is mediated by massless vector bosons (hypergluons), which self-interact so that the interaction has two additional features not present in Newtonian gravitation: (i) asymptotic freedom and (ii) color confinement. These two additional properties of the gravitational interaction negate the need for the notions of both dark matter and dark energy. (author)

  11. Particle Dark Matter: Status and Searches

    OpenAIRE

    Sandick, Pearl

    2010-01-01

    A brief overview is given of the phenomenology of particle dark matter and the properties of some of the most widely studied dark matter candidates. Recent developments in direct and indirect dark matter searches are discussed.

  12. DIOS (Diffuse Intergalactic Oxygen Surveyor): the Dark Baryon Exploring Mission

    Science.gov (United States)

    Tawara, Yuzuru; Ohashi, Takaya; Yamasaki, Noriko; Mitsuda, Kazuhisa

    2015-08-01

    More than half of the baryons are unidentified in the local Universe, and majority of them are thought to reside along the large-scale structure in the form of Warm-Hot Intergalactic Medium (WHIM). The 3-dimensional structure of WHIM will be probed by observing redshifted oxygen emission lines with high resolution X-ray spectrometers. DIOS (Diffuse Intergalactic Oxygen Surveyor) has been developed aiming for a launch by JAXA’s Epsilon Launch Vehicle around 2020. The payload consists of a 4-reflection X-ray telescope and a TES calorimeter array cooled by mechanical coolers. With a large grasp (area times f.o.v.) over 100 cm2 deg2, DIOS will identify 30-40% of dark baryons and will show us gas dynamics of cosmic plasmas from Earth’s megnetosphere to cluster outskirts. We describe the design and outstanding issues of DIOS.

  13. Vector Mesons and Baryon Resonances in Nuclear Matter

    OpenAIRE

    Post, M.; Mosel, U.

    2001-01-01

    We calculate the effect of many-body interactions in nuclear matter on the spectral function of $\\rho$ and $\\omega$ meson. In particular, we focus on the role played by baryon resonances in this context.

  14. Nonlocal gravity simulates dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Hehl, Friedrich W. [Institute for Theoretical Physics, University of Cologne, 50923 Koeln (Germany); Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211 (United States)], E-mail: hehl@thp.uni-koeln.de; Mashhoon, Bahram [Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, MO 65211 (United States)], E-mail: mashhoonb@missouri.edu

    2009-03-30

    A nonlocal generalization of Einstein's theory of gravitation is constructed within the framework of the translational gauge theory of gravity. In the linear approximation, the nonlocal theory can be interpreted as linearized general relativity but in the presence of 'dark matter' that can be simply expressed as an integral transform of matter. It is shown that this approach can accommodate the Tohline-Kuhn treatment of the astrophysical evidence for dark matter.

  15. Comparative testing of dark matter models with 9 HSB and 9 LSB galaxies

    CERN Document Server

    Kun, E; Keresztes, Z; Gergely, L Á

    2016-01-01

    We ensemble a database of 9 high-surface brightness (HSB) and 9 low-surface brightness (LSB) galaxies, for which both surface brightness density and spectroscopic rotation curve data are available in the literature, and are representative for the various morphologies. We use this dataset for a comparative testing of the Navarro-Frenk-White, the Einasto, and the pseudo-isothermal sphere dark matter models. We investigate the compatibility of the pure baryonic model and baryonic plus one of the three dark matter models with observations on the assembled galaxy database. When dark matter component is necessary to explain the spectroscopic rotational curves, we rank the models according to the goodness of fitting to the datasets. We construct the spatial luminosity density of the baryonic component based on the surface brightness profile of the galaxies. An axissymetric, baryonic mass model with variable axis ratios and three dark matter models are employed to fit the theoretical rotational velocity curves to the...

  16. Common Origin of Neutrino Mass, Dark Matter and Dirac Leptogenesis

    CERN Document Server

    Borah, Debasish

    2016-01-01

    We study the possibility of generating tiny Dirac neutrino masses at one loop level through the \\textit{scotogenic} mechanism such that one of the particles going inside the loop can be a stable cold dark matter (DM) candidate. Majorana mass terms of singlet fermions as well as tree level Dirac neutrino masses are prevented by incorporating the presence of additional discrete symmetries in a minimal fashion, which also guarantee the stability of the dark matter candidate. Due to the absence of total lepton number violation, the observed baryon asymmetry of the Universe is generated through the mechanism of Dirac leptogenesis where an equal and opposite amount of leptonic asymmetry is generated in the left and right handed sectors which are prevented from equilibration due to tiny Dirac Yukawa couplings. Dark matter relic abundance is generated through its usual freeze-out at a temperature much below the scale of leptogenesis. We constrain the relevant parameter space from neutrino mass, baryon asymmetry, Plan...

  17. Flavoured Dark Matter Beyond MFV

    CERN Document Server

    Blanke, Monika

    2014-01-01

    We review a model of quark flavoured dark matter with new flavour violating interactions. This simplified model describes Dirac fermionic dark matter that is charged under a new U(3) flavour symmetry and couples to right-handed down quarks via a scalar mediator. The corresponding coupling matrix is assumed to be the only new source of flavour violation, which we refer to as the Dark Minimal Flavour Violation (DMFV) hypothesis. This ansatz ensures the stability of dark matter. We discuss the phenomenology of the simplest DMFV model in flavour violating observables, LHC searches, and direct dark matter detection experiments. Especially interesting is the non-trivial interplay between the constraints from the different sectors.

  18. NASA's Dark Matter and Dark Energy Programs

    International Nuclear Information System (INIS)

    We present an overview of selected high value scientific results and prospects for future advances from NASA's “Dark” missions, i.e., those covering dark matter (DM) and dark energy (DE). This includes current missions HST, Chandra, Swift, GALEX, Suzaku, Fermi, and future missions JWST and WFIRST. These missions and earlier ones, such as WMAP, have brought about a revolution in our understanding of the fundamental properties of the universe – its age, rate of expansion, deceleration history, and composition (i.e., relative mix of luminous matter, dark matter, and dark energy). The next chapters in this story will be written by JWST and WFIRST. JWST was the highest priority of the 2000 Decadal Survey. It will observe in the near and medium infrared, and revolutionize our understanding of the high redshift universe. WFIRST is the highest ranked large space mission of the 2010 Decadal Survey. It is a NASA observatory designed to perform wide-field imaging and slitless spectroscopic surveys of the NIR sky (0.7 – 2.5μ). WFIRST will: (i) measure the expansion history of the universe, and thereby constrain dark energy, (ii) find Earth-like planets around other stars using microlensing, and (iii) perform surveys that are ∼100 times more sensitive than current NIR surveys

  19. Identification of All Dark Matter as Black Holes

    OpenAIRE

    Frampton, Paul H.

    2009-01-01

    For the universe I use dimensionless entropy $S/k = \\ln \\Omega$ for which the most convenient unit is the googol ($10^{100}$) and identify all dark matter as black holes whereupon the present entropy is about a thousand googols. While the energy of the universe has been established to be about 0.04 baryons, 0.24 dark matter and 0.72 dark energy, the cosmological entropy is almost entirely, about $(1 - 10^{-15})$, from black holes and only $10^{-15}$ from everything else. This identification o...

  20. AMS-02 fits dark matter

    Science.gov (United States)

    Balázs, Csaba; Li, Tong

    2016-05-01

    In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified dark matter model. We include known, standard astrophysical sources and a dark matter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the dark matter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the dark matter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the dark matter hypothesis within the uncertainties, but adding a dark matter contribution improves the fit to the data. Assuming, however, that dark matter is solely responsible for this improvement of the fit, it is difficult to evade the latest CMB limits in this model.

  1. Detectors calibration and research of luminescent materials for non baryonic dark matter detection; Calibration de detecteurs et recherche de materiaux luminescents pour la detection de la matiere noire non baryonique

    Energy Technology Data Exchange (ETDEWEB)

    Messous, M.Y.

    1995-03-01

    This work is dedicated to the characterization of luminescent materials in order to build bolometers for the simultaneous detection of heat an light in the search for WIMPs (Weakly Interacting Massive Particles) candidates for non baryonic dark matter. These double bolometers should enable the identification and measurement of recoil ions after collision between a WIMPs and material nucleus. In our search for highly luminescent materials, we have studied the emission spectra, the time response and the spectra response resulting from laser excitation or ionizing particles bombardment of some crystals such as CaF{sub 2}(Eu), CaF{sub 2}, CeF{sub 3}(Ce) and In{sub 2}Si{sub 2}O{sub 7}. These studies were conducted down to liquid Helium temperature (4 K). After showing the good performance of CaF{sub 2}(Eu) scintillator, we have measured the quenching effect resulting from {sup 19}F and Ca ions recoil in CaF{sub 2}(Eu). This was done at the 14 MeV Tandem accelerator of Bruyeres-Le-Chatel with a pulsed neutron beam, simulating the WIMPs. The data obtained allowed the exploitation of the results of the BPRS (Beijing - Rome - Paris - Saclay) experiments carried out at Gran-Sasso. This results showed a gain of up to an order of magnitude in the exclusion graph of axially coupled WIMPs compared to NaI. With the apparatus developed at IPN Lyon (Nuclear Physical Institute of Lyon), we have also measured the ionization induced by Ge ion recoils in Germanium detector, which is one of the most promising crystals for WIMPs detection in the energy range of 2.8 keV-37.8 keV. An ionization efficiency of 24% to 29% was obtained. (author). refs., figs., tabs.

  2. The dark side of cosmology: dark matter and dark energy.

    Science.gov (United States)

    Spergel, David N

    2015-03-01

    A simple model with only six parameters (the age of the universe, the density of atoms, the density of matter, the amplitude of the initial fluctuations, the scale dependence of this amplitude, and the epoch of first star formation) fits all of our cosmological data . Although simple, this standard model is strange. The model implies that most of the matter in our Galaxy is in the form of "dark matter," a new type of particle not yet detected in the laboratory, and most of the energy in the universe is in the form of "dark energy," energy associated with empty space. Both dark matter and dark energy require extensions to our current understanding of particle physics or point toward a breakdown of general relativity on cosmological scales. PMID:25745164

  3. Physics Beyond the Standard Model and Dark Matter

    CERN Document Server

    Murayama, Hitoshi

    2007-01-01

    In this lecture note, I discuss why many of us are expecting rich physics at the TeV scale, drawing analogies from the history of physics in the last century. Then I review some of the possible candidates of new physics at this energy scale. I also discuss why we believe much of the matter in the universe is not atoms (baryons) or compact astronomical objects, and hence requires physics beyond the standard model. Finally I discuss some of the candidates for the non-baryonic dark matter.

  4. Layers of deformed instantons in holographic baryonic matter

    CERN Document Server

    Preis, Florian

    2016-01-01

    We discuss homogeneous baryonic matter in the decompactified limit of the Sakai-Sugimoto model, improving existing approximations based on flat-space instantons. We allow for an anisotropic deformation of the instantons in the holographic and spatial directions and for a density-dependent distribution of arbitrarily many instanton layers in the bulk. Within our approximation, the baryon onset turns out to be a second-order phase transition, at odds with nature, and there is no transition to quark matter at high densities, at odds with expectations from QCD. This changes when we impose certain constraints on the shape of single instantons, motivated by known features of holographic baryons in the vacuum. Then, a first-order baryon onset and chiral restoration at high density are possible, and at sufficiently large densities two instanton layers are formed dynamically. Our results are a further step towards describing realistic, strongly interacting matter over a large density regime within a single model, desi...

  5. "Dark Matter searches at ATLAS"

    CERN Document Server

    Gustavino, Giuliano; The ATLAS collaboration

    2016-01-01

    Although the existence of Dark Matter is a well-established hypothesis to explain a range of astrophysical and cosmological measurements, its nature and particle properties still remain one of the greatest unsolved puzzles of particle and astro-particle physics. The collider experiments have developed a comprehensive search program in this sector looking at a wide spectrum of channels in which a Dark Matter evidence can be traced. In this context the last results using the data sample collected at LHC at the new centre-of-mass energy of 13 TeV will be presented giving an outlook of the Dark Matter search status in the ATLAS experiment.

  6. Indirect detection of dark matter

    International Nuclear Information System (INIS)

    This article is an experimental review of the status and prospects of indirect searches for dark matter. Experiments observe secondary particles such as positrons, antiprotons, antideuterons, gamma-rays and neutrinos which could originate from annihilations of dark matter particles in various locations in the galaxy. Data exist from some experiments which have been interpreted as hints of evidence for dark matter. These data and their interpretations are reviewed together with the new experiments which are planned to resolve the puzzles and make new measurements which could give unambiguous results

  7. Mixed dark matter from technicolor

    DEFF Research Database (Denmark)

    Belyaev, Alexander; T. Frandsen, Mads; Sannino, Francesco;

    2011-01-01

    We study natural composite cold dark matter candidates which are pseudo Nambu-Goldstone bosons (pNGB) in models of dynamical electroweak symmetry breaking. Some of these can have a significant thermal relic abundance, while others must be mainly asymmetric dark matter. By considering the thermal...... abundance alone we find a lower bound of MW on the pNGB mass when the (composite) Higgs is heavier than 115 GeV. Being pNGBs, the dark matter candidates are in general light enough to be produced at the LHC....

  8. Casting light on dark matter

    International Nuclear Information System (INIS)

    The prospects for detecting a candidate supersymmetric dark matter particle at the LHC are reviewed, and compared with the prospects for direct and indirect searches for astrophysical dark matter. The discussion is based on a frequentist analysis of the preferred regions of the Minimal supersymmetric extension of the Standard Model with universal soft supersymmetry breaking (the CMSSM). LHC searches may have good chances to observe supersymmetry in the near future - and so may direct searches for astrophysical dark matter particles, whereas indirect searches may require greater sensitivity, at least within the CMSSM.

  9. (Mainly) axion dark matter

    CERN Document Server

    Baer, Howard

    2015-01-01

    The strong CP problem of QCD is at heart a problem of naturalness: why is the F\\tilde{F} term highly suppressed in the QCD Lagrangian when it seems necessary to explain why there are three and not four light pions? The most elegant solution posits a spontaneously broken Peccei-Quinn (PQ) symmetry which requires the existence of the axion field a. The axion field settles to the minimum of its potential thus removing the offensive term but giving rise to the physical axion whose coherent oscillations can make up the cold dark matter. Only now are experiments such as ADMX beginning to explore QCD axion parameter space. Since a bonafide scalar particle-- the Higgs boson-- has been discovered, one might expect its mass to reside at the axion scale f_a~ 10^{11} GeV. The Higgs mass is elegantly stabilized by supersymmetry: in this case the axion is accompanied by its axino and saxion superpartners. Requiring naturalness also in the electroweak sector implies higgsino-like WIMPs so then we expect mixed axion-WIMP dar...

  10. Probing Gravitational Dark Matter

    CERN Document Server

    Ren, Jing

    2015-01-01

    So far all evidences of dark matter (DM) come from astrophysical and cosmological observations, due to the gravitational interactions of DM. It is possible that the true DM particle in the universe joins gravitational interactions only, but nothing else. Such a Gravitational DM (GDM) acts as a weakly interacting massive particle (WIMP), which is conceptually simple and attractive. In this work, we explore this direction by constructing the simplest scalar GDM particle $\\chi_s$. It is a $\\mathbb{Z}_2$ odd singlet under the standard model (SM) gauge group, and naturally joins the unique dimension-4 interaction with Ricci curvature, $\\xi_s\\chi_s^2{\\cal R}$, where $\\xi_s$ is the dimensionless nonminimal coupling. We demonstrate that this gravitational interaction $\\xi_s\\chi_s^2{\\cal R}$, together with Higgs-curvature nonminimal coupling term $\\xi_h H^\\dag H {\\cal R}$, induces effective couplings between $\\chi_s^2$ and SM fields which can account for the observed DM thermal relic abundance. We analyze the annihila...

  11. Bright Galaxies, Dark Matters

    Science.gov (United States)

    Rubin, Vera

    In 1965, Vera Rubin was the first woman permitted to observe at Palomar Observatory. In the intervening years, she has become one of the world's finest and most respected astronomers. This particular collection of essays is compiled from work written over the past 15 years and deals with a variety of subjects in astronomy and astrophysics, specifically galaxies and dark matter. The book also contains biographical sketches of astronomers who have been colleagues and friends, providing a stimulating view of a woman in science. About the Author Since 1965 Vera Rubin has been a staff member at the Department of Terrestrial Magnetism of the Carnegie Institution of Washington. Dr. Rubin has authored nearly 200 papers on the structure of our galaxy, motions within other galaxies, and large scale motions in the universe. She has been a distinguished visiting astronomer at the Cerro Tololo Inter American Observatory in Chile; a Chancellor's Distinguished Professor at the University of California, Berkeley; a President's Distinguished Visitor at Vassar College; and a Beatrice Tinsley visiting professor at the University of Texas, Austin.

  12. Novel frameworks for Dark Matter and neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Daniel

    2013-12-18

    The established light neutrino masses and the Dark Matter of the Universe both require physics beyond the Standard Model for their theoretical explanation. Models that provide a common framework for these two issues are very attractive. In particular, radiative mechanisms naturally yield light neutrino masses due to loop suppression factors. These corrections can comprise a link to the physics of Dark Matter. In most considerations, the Dark Matter relic density is produced by freeze-out. This thesis contributes to the fields of radiative neutrino masses and frozen-out Dark Matter. In detail, it is shown that in the Ma-model, right-handed neutrino Dark Matter can be directly detected by photon exchange at one-loop level. The Zee-Babu-model is extended such that it enjoys a global symmetry based on baryon and lepton number. This symmetry generates light neutrino masses and a mass for a stable Dark Matter particle by its spontaneous breaking. Moreover, this thesis provides a new production mechanism for keV sterile neutrino Dark Matter, which is based on the freeze-in scenario. In particular, keV sterile neutrino Dark Matter produced by the decay of a frozen-in scalar is investigated.

  13. Baryogenesis and dark matter through a Higgs asymmetry.

    Science.gov (United States)

    Servant, Géraldine; Tulin, Sean

    2013-10-11

    In addition to explaining the masses of elementary particles, the Higgs boson may have far-reaching implications for the generation of the matter content in the Universe. For instance, the Higgs boson plays a key role in two main theories of baryogenesis, namely, electroweak baryogenesis and leptogenesis. In this Letter, we propose a new cosmological scenario where the Higgs chemical potential mediates asymmetries between visible and dark matter sectors, either generating a baryon asymmetry from a dark matter asymmetry or vice versa. We illustrate this mechanism with a simple model with two new fermions coupled to the Higgs boson and discuss the associated signatures. PMID:24160589

  14. Skew-flavored dark matter

    Science.gov (United States)

    Agrawal, Prateek; Chacko, Zackaria; Fortes, Elaine C. F. S.; Kilic, Can

    2016-05-01

    We explore a novel flavor structure in the interactions of dark matter with the Standard Model. We consider theories in which both the dark matter candidate, and the particles that mediate its interactions with the Standard Model fields, carry flavor quantum numbers. The interactions are skewed in flavor space, so that a dark matter particle does not directly couple to the Standard Model matter fields of the same flavor, but only to the other two flavors. This framework respects minimal flavor violation and is, therefore, naturally consistent with flavor constraints. We study the phenomenology of a benchmark model in which dark matter couples to right-handed charged leptons. In large regions of parameter space, the dark matter can emerge as a thermal relic, while remaining consistent with the constraints from direct and indirect detection. The collider signatures of this scenario include events with multiple leptons and missing energy. These events exhibit a characteristic flavor pattern that may allow this class of models to be distinguished from other theories of dark matter.

  15. Unified Description of Dark Energy and Dark Matter

    OpenAIRE

    Petry, Walter

    2008-01-01

    Dark energy in the universe is assumed to be vacuum energy. The energy-momentum of vacuum is described by a scale-dependent cosmological constant. The equations of motion imply for the density of matter (dust) the sum of the usual matter density (luminous matter) and an additional matter density (dark matter) similar to the dark energy. The scale-dependent cosmological constant is given up to an exponent which is approximated by the experimentally decided density parameters of dark matter and...

  16. The Dark Matter of Biology.

    Science.gov (United States)

    Ross, Jennifer L

    2016-09-01

    The inside of the cell is full of important, yet invisible species of molecules and proteins that interact weakly but couple together to have huge and important effects in many biological processes. Such "dark matter" inside cells remains mostly hidden, because our tools were developed to investigate strongly interacting species and folded proteins. Example dark-matter species include intrinsically disordered proteins, posttranslational states, ion species, and rare, transient, and weak interactions undetectable by biochemical assays. The dark matter of biology is likely to have multiple, vital roles to regulate signaling, rates of reactions, water structure and viscosity, crowding, and other cellular activities. We need to create new tools to image, detect, and understand these dark-matter species if we are to truly understand fundamental physical principles of biology. PMID:27602719

  17. Dark Matter search at LHC

    CERN Document Server

    Pazzini, Jacopo

    2016-01-01

    The results of recent searches for dark matter at the Large Hadron Collider at CERN are reported.The searches for dark matter performed with the first data collected during the LHC Run-2 by the CMS and ATLAS collaborations, corresponding to 2.1~\\fb and 3.2~\\fb of proton-proton collisions at $\\sqrt{s}=13~\\TeV$ respectively, are presented and categorized according to the event topology characteristics.No excesses are found above the standard model expectations and the results are interpreted in terms of upper limits in the production of dark matter using simplified theory models.The results are also translated into limits on the dark matter-nucleon spin-dependent and spin-independent cross section to compare with the results of direct detection experiments.

  18. The LZ dark matter experiment

    Science.gov (United States)

    McKinsey, D. N.; LZ Collaboration

    2016-05-01

    The LUX and ZEPLIN collaborations have merged to construct a 7 tonne two-phase Xe dark matter detector, known as LUX-ZEPLIN or LZ. Chosen as one of the Generation 2 suite of dark matter direct detection experiments, LZ will probe spin-independent WIMP-nucleon cross sections down to 2 × 10-48 cm2 at 50 GeV/c2 within 3 years of operation, covering a substantial range of theoretically-motivated dark matter candidates. Along with dark matter interactions with Xe nuclei, LZ will also be sensitive to solar neutrinos emitted by the pp fusion process in the sun, neutrinos emitted by a nearby supernova and detected by coherent neutrino-nucleus scattering, certain classes of axions and axion-like particles, and neutrinoless double-beta decay of 136Xe. The design of LZ is presented, along with its expected backgrounds and projected sensitivity.

  19. Weak Lensing: Dark Matter, Dark Energy

    International Nuclear Information System (INIS)

    The light rays from distant galaxies are deflected by massive structures along the line of sight, causing the galaxy images to be distorted. Measurements of these distortions, known as weak lensing, provide a way of measuring the distribution of dark matter as well as the spatial geometry of the universe. I will describe the ideas underlying this approach to cosmology. With planned large imaging surveys, weak lensing is a powerful probe of dark energy. I will discuss the observational challenges ahead and recent progress in developing multiple, complementary approaches to lensing measurements.

  20. A New Cosmological Paradigm the Cosmological Constant and Dark Matter

    CERN Document Server

    Krauss, L M

    1998-01-01

    The Standard Cosmological Model of the 1980's is no more. I describe the definitive evidence that the density of matter is insufficient to result in a flat universe, as well as the mounting evidence that the cosmological constant is not zero. I finally discuss the implications of these results for particle physics and direct searches for non-baryonic dark matter, and demonstrate that the new news is good news.

  1. The search for decaying Dark Matter

    CERN Document Server

    Herder, J W den; Ruchayskiy, O; Abazajian, K; Frenk, C; Hansen, S; Jonker, P; Kouveliotou, C; Lesgourgues, J; Neronov, A; Ohashi, T; Paerels, F; Paltani, S; Piro, L; Pohl, M; Shaposhnikov, M; Silk, J; Valle, J

    2009-01-01

    We propose an X-ray mission called Xenia to search for decaying superweakly interacting Dark Matter particles (super-WIMP) with a mass in the keV range. The mission and its observation plan are capable of providing a major break through in our understanding of the nature of Dark Matter (DM). It will confirm, or reject, predictions of a number of particle physics models by increasing the sensitivity of the search for decaying DM by about two orders of magnitude through a wide-field imaging X-ray spectrometer in combination with a dedicated observation program. The proposed mission will provide unique limits on the mixing angle and mass of neutral leptons, right handed partners of neutrinos, which are important Dark Matter candidates. The existence of these particles is strongly motivated by observed neutrino flavor oscillations and the problem of baryon asymmetry of the Universe. In super-WIMP models, the details of the formation of the cosmic web are different from those of LambdaCDM. The proposed mission wil...

  2. The minimal model of fermionic dark matter

    OpenAIRE

    Kim, Yeong Gyun; Lee, Kang Young

    2006-01-01

    We explore the minimal extension of the Standard Model with fermionic cold dark matter. The interactions between the dark matter and the Standard Model matters are described by the non-renormalizable dimension-5 term. We show that the measured relic abundance of the cold dark matter can be explained in our model and predict the direct detection cross section. The direct search of the dark matter provides severe constraints on the mass and coupling of the minimal fermionic dark matter with res...

  3. A History of Dark Matter

    OpenAIRE

    Bertone, Gianfranco; Hooper, Dan

    2016-01-01

    Although dark matter is a central element of modern cosmology, the history of how it became accepted as part of the dominant paradigm is often ignored or condensed into a brief anecdotical account focused around the work of a few pioneering scientists. The aim of this review is to provide the reader with a broader historical perspective on the observational discoveries and the theoretical arguments that led the scientific community to adopt dark matter as an essential part of the standard cos...

  4. The Galaxy Dark Matter Connection

    OpenAIRE

    Bosch, Frank C. van den; Yang, Xiaohu; Mo, H. J.

    2004-01-01

    What galaxy lives in what halo? The answer to this simple question holds important information regarding galaxy formation and evolution. We describe a new statistical technique to link galaxies to their dark matter haloes, or light to mass, using the clustering properties of galaxies as function of their luminosity. The galaxy-dark matter connection thus established, and parameterized through the conditional luminosity function, indicates the presence of two characteristic scales in galaxy fo...

  5. A History of Dark Matter

    CERN Document Server

    Bertone, Gianfranco

    2016-01-01

    Although dark matter is a central element of modern cosmology, the history of how it became accepted as part of the dominant paradigm is often ignored or condensed into a brief anecdotical account focused around the work of a few pioneering scientists. The aim of this review is to provide the reader with a broader historical perspective on the observational discoveries and the theoretical arguments that led the scientific community to adopt dark matter as an essential part of the standard cosmological model.

  6. Dark matter triggers of supernovae

    Science.gov (United States)

    Graham, Peter W.; Rajendran, Surjeet; Varela, Jaime

    2015-09-01

    The transit of primordial black holes through a white dwarf causes localized heating around the trajectory of the black hole through dynamical friction. For sufficiently massive black holes, this heat can initiate runaway thermonuclear fusion causing the white dwarf to explode as a supernova. The shape of the observed distribution of white dwarfs with masses up to 1.25 M⊙ rules out primordial black holes with masses ˜1019- 1020 gm as a dominant constituent of the local dark matter density. Black holes with masses as large as 1024 gm will be excluded if recent observations by the NuStar Collaboration of a population of white dwarfs near the galactic center are confirmed. Black holes in the mass range 1020- 1022 gm are also constrained by the observed supernova rate, though these bounds are subject to astrophysical uncertainties. These bounds can be further strengthened through measurements of white dwarf binaries in gravitational wave observatories. The mechanism proposed in this paper can constrain a variety of other dark matter scenarios such as Q balls, annihilation/collision of large composite states of dark matter and models of dark matter where the accretion of dark matter leads to the formation of compact cores within the star. White dwarfs, with their astronomical lifetimes and sizes, can thus act as large spacetime volume detectors enabling a unique probe of the properties of dark matter, especially of dark matter candidates that have low number density. This mechanism also raises the intriguing possibility that a class of supernova may be triggered through rare events induced by dark matter rather than the conventional mechanism of accreting white dwarfs that explode upon reaching the Chandrasekhar mass.

  7. A History of Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Bertone, Gianfranco [U. Amsterdam, GRAPPA; Hooper, Dan [Fermilab

    2016-05-16

    Although dark matter is a central element of modern cosmology, the history of how it became accepted as part of the dominant paradigm is often ignored or condensed into a brief anecdotical account focused around the work of a few pioneering scientists. The aim of this review is to provide the reader with a broader historical perspective on the observational discoveries and the theoretical arguments that led the scientific community to adopt dark matter as an essential part of the standard cosmological model.

  8. Theories of particle dark matter

    International Nuclear Information System (INIS)

    This brief review outlines some of the most attractive theoretical motivations for particle dark matter, and illustrates how they fit into the bigger context of physics beyond the Standard Model. Particular emphasis is given to the generic properties of theories of dark matter, and how the mechanism by which it interacts with the Standard Model particles influences its phenomenology. Brief descriptions of the most popular models, including supersymmetric theories and theories with universal extra dimensions are discussed. (authors)

  9. Dark Matter searches at CMS

    CERN Document Server

    Kumar, Ashok

    2016-01-01

    This talk describes searches for directly produced Dark Matter particles in CMS. The searches are performed using the datasets recorded with the CMS detector in proton-proton collisions at center-of-mass energies of 8 and 13 TeV. Final states with a monojet, monophoton, and monolepton signature are among the final states considered, as well as dark-matter particles produced in association with bottom and top quarks.

  10. Tachyonic models of dark matter

    CERN Document Server

    Nikitin, Igor

    2016-01-01

    We consider a spherically symmetric stationary problem in General Relativity, including a black hole, inflow of normal and tachyonic matter and outflow of tachyonic matter. Computations in a weak field limit show that the resulting concentration of matter around the black hole leads to gravitational effects equivalent to those associated with dark matter halo. In particular, the model reproduces asymptotically constant galactic rotation curves, if the tachyonic flows of the central supermassive black hole in the galaxy are considered as a main contribution.

  11. Dark Energy - Dark Matter Unification: Generalized Chaplygin Gas Model

    OpenAIRE

    Bertolami, Orfeu

    2005-01-01

    We review the main features of the generalized Chaplygin gas (GCG) proposal for unification of dark energy and dark matter and discuss how it admits an unique decomposition into dark energy and dark matter components once phantom-like dark energy is excluded. In the context of this approach we consider structure formation and show that unphysical oscillations or blow-up in the matter power spectrum are not present. Moreover, we demonstrate that the dominance of dark energy occurs about the ti...

  12. A Theory of Dark Matter Superfluidity

    CERN Document Server

    Berezhiani, Lasha

    2015-01-01

    We propose a novel theory of dark matter (DM) superfluidity that matches the successes of the LambdaCDM model on cosmological scales while simultaneously reproducing the MOdified Newtonian Dynamics (MOND) phenomenology on galactic scales. The DM and MOND components have a common origin, representing different phases of a single underlying substance. DM consists of axion-like particles with mass of order eV and strong self-interactions. The condensate has a polytropic equation of state P~rho^3 giving rise to a superfluid core within galaxies. Instead of behaving as individual collisionless particles, the DM superfluid is more aptly described as collective excitations. Superfluid phonons, in particular, are assumed to be governed by a MOND-like effective action and mediate a MONDian acceleration between baryonic matter particles. Our framework naturally distinguishes between galaxies (where MOND is successful) and galaxy clusters (where MOND is not): due to the higher velocity dispersion in clusters, and corres...

  13. Asymmetric dark matter from spontaneous cogenesis in the supersymmetric standard model

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Kohei [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Yamaguchi, Masahide [Tokyo Institute of Technology (Japan). Dept. of Physics

    2012-01-15

    The observational relation between the density of baryon and dark matter in the Universe, {omega}{sub DM}/{omega}{sub B}{approx_equal}5, is one of the most difficult problems to solve in modern cosmology. We discuss a scenario that explains this relation by combining the asymmetric dark matter scenario and the spontaneous baryogenesis associated with the flat direction in the supersymmetric standard model. A part of baryon asymmetry is transferred to charge asymmetry D that dark matter carries, if a symmetry violating interaction that works at high temperature breaks not only B-L but also D symmetries simultaneously. In this case, the present number density of baryon and dark matter can be same order if the symmetric part of dark matter annihilates sufficiently. Moreover, the baryon number density can be enhanced as compared to that of dark matter if another B-L violating interaction is still in thermal equilibrium after the spontaneous genesis of dark matter, which accommodates a TeV scale asymmetric dark matter model. (orig.)

  14. Light Dark Matter

    Science.gov (United States)

    Cassé, M.; Fayet, P.

    The SPI spectrometer aboard of the INTEGRAL satellite has released a map of the e^+e- annihilation emission line of unprecedented quality, showing that most of the photons arise from a region coinciding with the stellar bulge of the Milky Way. The impressive intensity (≃ 10-3 photon cm-2 s-1) and morphology (round and wide) of the emission is begging an explanation. Different classes of astrophysical objects could inject positrons in the interstellar medium of the bulge, but the only acceptable ones should inject them at energies low enough to avoid excessive bremsstrahlung emission in the soft gamma ray regime. Among the ~ MeV injectors, none seems generous enough to sustain the high level of annihilation observed. Even the most profuse candidate, namely the β+ radioactivity of 56Co nuclei created and expelled in the interstellar medium by explosive nucleosynthesis of type Ia supernovae, falls short explaining the phenomenon due to the small fraction of positrons leaking out from the ejecta (≈ 3%), together with the low SNIa rate in the bulge (≈ 0.03 per century). It is therefore worth exploring alternative solutions, as for instance, the idea that the source of the positrons is the annihilation of light dark matter (LDM) particles of the kind recently proposed, totally independently, by Bœhm and Fayet. Assuming that LDM is the culprit, crucial constraints on the characteristics (mass and annihilation cross-section) of the associated particle may be discussed, combining direct gamma ray observations and models of the early Universe. In particular, the mass of the LDM particles should be significantly less than 100 MeV, so that the e+ and e- resulting from their annihilations do not radiate exceedingly through bremsstrahlung in the interstellar gas of the galactic bulge.

  15. Electroweak interactions and dark baryons in the sextet BSM model with a composite Higgs particle

    Science.gov (United States)

    Fodor, Zoltan; Holland, Kieran; Kuti, Julius; Mondal, Santanu; Nogradi, Daniel; Wong, Chik Him

    2016-07-01

    The electroweak interactions of a strongly coupled gauge theory are discussed with an outlook beyond the Standard Model (BSM) under global and gauge anomaly constraints. The theory is built on a minimal massless fermion doublet of the SU(2) BSM flavor group (bsm-flavor) with a confining gauge force at the TeV scale in the two-index symmetric (sextet) representation of the BSM SU(3) color gauge group (bsm-color). The intriguing possibility of near-conformal sextet gauge dynamics could lead to the minimal realization of the composite Higgs mechanism with a light 0++ scalar, far separated from strongly coupled resonances of the confining gauge force in the 2-3 TeV range, distinct from Higgsless technicolor. In previous publications we have presented results for the meson spectrum of the theory, including the light composite scalar, which is perhaps the emergent Higgs impostor. Here we discuss the critically important role of the baryon spectrum in the sextet model investigating its compatibility with what we know about thermal evolution of the early Universe including its galactic and terrestrial relics. For an important application, we report the first numerical results on the baryon spectrum of this theory from nonperturbative lattice simulations with baryon correlators in the staggered fermion implementation of the strongly coupled gauge sector. The quantum numbers of composite baryons and their spectroscopy from lattice simulations are required inputs for exploring dark matter contributions of the sextet BSM model, as outlined for future work.

  16. Dark matter beams at LBNF

    Science.gov (United States)

    Coloma, Pilar; Dobrescu, Bogdan A.; Frugiuele, Claudia; Harnik, Roni

    2016-04-01

    High-intensity neutrino beam facilities may produce a beam of light dark matter when protons strike the target. Searches for such a dark matter beam using its scattering in a nearby detector must overcome the large neutrino background. We characterize the spatial and energy distributions of the dark matter and neutrino beams, focusing on their differences to enhance the sensitivity to dark matter. We find that a dark matter beam produced by a Z ' boson in the GeV mass range is both broader and more energetic than the neutrino beam. The reach for dark matter is maximized for a detector sensitive to hard neutral-current scatterings, placed at a sizable angle off the neutrino beam axis. In the case of the Long-Baseline Neutrino Facility (LBNF), a detector placed at roughly 6 degrees off axis and at a distance of about 200 m from the target would be sensitive to Z ' couplings as low as 0.05. This search can proceed symbiotically with neutrino measurements. We also show that the MiniBooNE and MicroBooNE detectors, which are on Fermilab's Booster beamline, happen to be at an optimal angle from the NuMI beam and could perform searches with existing data. This illustrates potential synergies between LBNF and the short-baseline neutrino program if the detectors are positioned appropriately.

  17. Dark matter beams at LBNF

    CERN Document Server

    Coloma, Pilar; Frugiuele, Claudia; Harnik, Roni

    2015-01-01

    High-intensity neutrino beam facilities may produce a beam of light dark matter when protons strike the target. Searches for such a dark matter beam using its scattering in a nearby detector must overcome the large neutrino background. We characterize the spatial and energy distributions of the dark matter and neutrino beams, focusing on their differences to enhance the sensitivity to dark matter. We find that a dark matter beam produced by a $Z'$ boson in the GeV mass range is both broader and more energetic than the neutrino beam. The reach for dark matter is maximized for a detector sensitive to hard neutral-current scatterings, placed at a sizable angle off the neutrino beam axis. In the case of the Long-Baseline Neutrino Facility (LBNF), a detector placed at roughly 6 degrees off axis and at a distance of about 200 m from the target would be sensitive to $Z'$ couplings as low as 0.05. This search can proceed symbiotically with neutrino measurements. We also show that the MiniBooNE and MicroBooNE detector...

  18. Reionization and dark matter decay

    CERN Document Server

    Oldengott, Isabel M; Schwarz, Dominik J

    2016-01-01

    Cosmic reionization and dark matter decay can impact observations of the cosmic microwave sky in a similar way. A simultaneous study of both effects is required to constrain unstable dark matter from cosmic microwave background observations. We compare two reionization models with and without dark matter decay. We find that a reionization model that fits also data from quasars and star forming galaxies results in tighter constraints on the reionization optical depth $\\tau_{\\text{reio}}$, but weaker constraints on the spectral index $n_{\\text{s}}$ than the conventional parametrization. We use the Planck 2015 data to constrain the effective decay rate of dark matter to $\\Gamma_{\\rm eff} < 2.9 \\times 10^{-25}/$s at $95$\\% C.L. This limit is robust and model independent. It holds for any type of decaying dark matter and it depends only weakly on the chosen parametrization of astrophysical reionization. For light dark matter particles that decay exclusively into electromagnetic components this implies a limit o...

  19. Dark matter and global symmetries

    Science.gov (United States)

    Mambrini, Yann; Profumo, Stefano; Queiroz, Farinaldo S.

    2016-09-01

    General considerations in general relativity and quantum mechanics are known to potentially rule out continuous global symmetries in the context of any consistent theory of quantum gravity. Assuming the validity of such considerations, we derive stringent bounds from gamma-ray, X-ray, cosmic-ray, neutrino, and CMB data on models that invoke global symmetries to stabilize the dark matter particle. We compute up-to-date, robust model-independent limits on the dark matter lifetime for a variety of Planck-scale suppressed dimension-five effective operators. We then specialize our analysis and apply our bounds to specific models including the Two-Higgs-Doublet, Left-Right, Singlet Fermionic, Zee-Babu, 3-3-1 and Radiative See-Saw models. Assuming that (i) global symmetries are broken at the Planck scale, that (ii) the non-renormalizable operators mediating dark matter decay have O (1) couplings, that (iii) the dark matter is a singlet field, and that (iv) the dark matter density distribution is well described by a NFW profile, we are able to rule out fermionic, vector, and scalar dark matter candidates across a broad mass range (keV-TeV), including the WIMP regime.

  20. Antideuterons from dark matter decay

    International Nuclear Information System (INIS)

    Recent observations of a large excess of cosmic-ray positrons at high energies have raised a lot of interest in leptonic decay modes of dark matter particles. Nevertheless, dark matter particles in the Milky Way halo could also decay hadronically, producing not only a flux of antiprotons but also a flux of antideuterons. We show that for certain choices of parameters the antideuteron flux from dark matter decay can be much larger than the purely secondary flux from spallation of cosmic rays on the interstellar medium, while the total antiproton flux remains consistent with present observations. We show that if the dark matter particle is sufficiently light, the antideuteron flux from dark matter decay could even be within the reach of planned experiments such as AMS-02 or GAPS. Furthermore, we discuss the prospects to observe the antideuteron flux in the near future if the steep rise in the positron fraction reported by the PAMELA collaboration is interpreted in terms of the decay of dark matter particles

  1. Dark matter and dark energy: approaches and constraints

    Science.gov (United States)

    Zakharov, Alexander

    We will introduce problems of Dark Matter (DM) and Dark Energy (DE), namely we will describe a development of these concepts and their present status. We will demonstrate ap-proaches to these problems. As specific issues we will discuss limits on DM concentration near the black hole at the Galactic Center and ways to solve DE problem introducing alternative theories of gravity such as f (R)-theories. The existence of dark matter (DM) at scales of few pc down to 10-5 pc around the centers of galaxies and in particular in the Galactic Center region has been considered in the literature. Under the assumption that such a DM clump, principally constituted by non-baryonic matter (like WIMPs) does exist at the center of our galaxy, the study of the γ-ray emission from the Galactic Center region allows us to constrain both the mass and the size of this DM sphere. Moreover, if a DM cusp does exist around the Galactic Center it could modify the trajectories of stars moving around it in a sensible way depending on the DM mass distribution. Here, we discuss the constraints that can be obtained with the orbit analysis of stars (as S2 and S16) moving inside the DM concentration with present and next generations of large telescopes. In particular, consideration of the S2 star apoastron shift may allow improving limits on the DM mass and size. We will describe severe constraints from Solar system data on parameters f (R) = Rn theories, where n = 1 corresponds to the standard general relativistic case. 1. A. F. Zakharov, A.A. Nucita, F. De Paolis, G. Ingrosso: Solar system constraints on Rn gravity, Phys. Rev. D 74, 107101, (2006). 2. A. F. Zakharov, A.A. Nucita, F. De Paolis, G. Ingrosso: Apoastron shift constraints on dark matter distribution at the Galactic Center, Phys. Rev. D 76, 062001, (2007). 3. A.F. Zakharov, S. Capozziello, F. De Paolis, G. Ingrosso, A.A. Nucita, The Role of Dark Matter and Dark Energy in Cosmological Models: Theoretical Overview, Space Sci. Rev. 148

  2. Novel Frameworks for Dark Matter and Neutrino Masses

    Science.gov (United States)

    Schmidt, Daniel

    2013-12-01

    The established light neutrino masses and the Dark Matter of the Universe both require physics beyond the Standard Model for their theoretical explanation. Models that provide a common framework for these two issues are very attractive. In particular, radiative mechanisms naturally yield light neutrino masses due to loop suppression factors. These corrections can comprise a link to the physics of Dark Matter. In most considerations, the Dark Matter relic density is produced by freeze-out. This thesis contributes to the elds of radiative neutrino masses and frozen-out Dark Matter. In detail, it is shown that in the Ma-model, right-handed neutrino Dark Matter can be directly detected by photon exchange at one-loop level. The Zee{Babu-model is extended such that it enjoys a global symmetry based on baryon and lepton number. This symmetry generates light neutrino masses and a mass for a stable Dark Matter particle by its spontaneous breaking. Moreover, this thesis provides a new production mechanism for keV sterile neutrino Dark Mattetr, which is based on the freeze-in scenario. In particular, keV sterile neutrino Dark Matter produced by the decay of a frozen-in scalar is investigated.

  3. Dark halo baryons not in ancient halo white dwarfs

    OpenAIRE

    Crézé, M.; Mohan, V; Robin, A.C.; Reylé, C.; Mc Cracken, H.,; Cuillandre, J.-C.; Le Fèvre, O.; Mellier, Y

    2004-01-01

    accepted in Astronomy and Astrophysics (19-05-2004) Having ruled out the possibility that stellar objects are the main contributor of the dark matter embedding galaxies, microlensing experiments cannot exclude the hypothesis that a significant fraction of the Milky Way dark halo might be made of MACHOs with masses in the range $0.5-0.8 \\msun$. Ancient white dwarfs are generally considered the most plausible candidates for such MACHOs. We report the results of a search for such white dwarfs...

  4. Constraining warm dark matter with cosmic shear power spectra

    International Nuclear Information System (INIS)

    We investigate potential constraints from cosmic shear on the dark matter particle mass, assuming all dark matter is made up of light thermal relic particles. Given the theoretical uncertainties involved in making cosmological predictions in such warm dark matter scenarios we use analytical fits to linear warm dark matter power spectra and compare (i) the halo model using a mass function evaluated from these linear power spectra and (ii) an analytical fit to the non-linear evolution of the linear power spectra. We optimistically ignore the competing effect of baryons for this work. We find approach (ii) to be conservative compared to approach (i). We evaluate cosmological constraints using these methods, marginalising over four other cosmological parameters. Using the more conservative method we find that a Euclid-like weak lensing survey together with constraints from the Planck cosmic microwave background mission primary anisotropies could achieve a lower limit on the particle mass of 2.5 keV

  5. Does Bulk Viscosity Create a Viable Unified Dark Matter Model?

    CERN Document Server

    Li, Baojiu

    2009-01-01

    We investigate in detail the possibility that a single imperfect fluid with bulk viscosity can replace the need for separate dark matter and dark energy in cosmological models. With suitable choices of model parameters, we show that the background cosmology in this model can mimic that of a LCDM Universe to high precision. However, as the cosmic expansion goes through the decelerating-accelerating transition, the density perturbations in this fluid are rapidly damped out. We show that,although this does not significantly affect structure formation in baryonic matter, it makes the gravitational potential decay rapidly at late times, leading to modifications in predictions of cosmological observables such as the CMB power spectrum and weak lensing. This model of unified dark matter is thus difficult to reconcile with astronomical observations. We also clarify the differences with respect to other unified dark matter models where the fluid is barotropic, i.e., p=p(rho), such as the (generalized) Chaplygin gas mo...

  6. Cosmological Evolution With Interaction Between Dark Energy And Dark Matter

    OpenAIRE

    Bolotin, Yu. L.; Kostenko, A.; Lemets, O. A.; Yerokhin, D. A.

    2013-01-01

    In this review we consider in detail different theoretical topics associated with interaction in the dark sector. We study linear and nonlinear interactions which depend on the dark matter and dark energy densities. We consider a number of different models (including the holographic dark energy and dark energy in a fractal universe) with interacting dark energy (DE) and dark matter (DM), have done a thorough analysis of these models. The main task of this review was not only to give an idea a...

  7. The search for dark matter

    International Nuclear Information System (INIS)

    Experiments housed deep underground are searching for new particles that could simultaneously solve one of the biggest mysteries in astrophysics and reveal what lies beyond the Standard Model of particle physics. Physicists are very particular about balancing budgets. Energy, charge and momentum all have to be conserved and often money as well. Astronomers were therefore surprised and disturbed to learn in the 1930s that our own Milky Way galaxy behaved as if it contained more matter than could be seen with telescopes. This puzzling non-luminous matter became known as ''dark matter'' and we now know that over 90% of the matter in the entire universe is dark. In later decades the search for this dark matter shifted from the heavens to the Earth. In fact, the search for dark matter went underground. Today there are experiments searching for dark matter hundreds and thousands of metres below ground in mines, road tunnels and other subterranean locations. These experiments are becoming more sensitive every year and are beginning to test various new models and theories in particle physics and cosmology. (UK)

  8. Dark matter as the Bose-Einstein condensation in loop quantum cosmology

    OpenAIRE

    Atazadeh, K.; Darabi, F.; M. Mousavi

    2016-01-01

    We consider the FLRW universe in a loop quantum cosmological model filled with the radiation, baryonic matter (with negligible pressure), dark energy and dark matter. The dark matter sector is supposed to be of Bose-Einstein condensate type. The Bose-Einstein condensation process in a cosmological context by supposing it as an approximate first order phase transition, has been already studied in the literature. Here, we study the evolution of the physical quantities related to the early unive...

  9. Vacuum Pressure, Dark Energy, and Dark Matter

    OpenAIRE

    Bogusław Broda; Michał Szanecki

    2011-01-01

    It has been argued that the correct, that is, positive, sign of quantum vacuum energy density, or, more properly, negative sign of quantum vacuum pressure, requires not a very large, and to some extent model-independent, number, for example, ∼100, of additional, undiscovered fundamental bosonic particle species, absent in the standard model. Interpretation of the new particle species in terms of dark matter ones permits to qualitatively, and even quantitatively, connect all the three concepts...

  10. Review of strongly-coupled composite dark matter models and lattice simulations

    OpenAIRE

    Kribs, Graham D.; Neil, Ethan T.

    2016-01-01

    We review models of new physics in which dark matter arises as a composite bound state from a confining strongly-coupled non-Abelian gauge theory. We discuss several qualitatively distinct classes of composite candidates, including dark mesons, dark baryons, and dark glueballs. We highlight some of the promising strategies for direct detection, especially through dark moments, using the symmetries and properties of the composite description to identify the operators that dominate the interact...

  11. Detecting dark matter using centrifuging techniques

    OpenAIRE

    Mitra, S.; Foot, R.

    2003-01-01

    A new and inexpensive technique for detecting self interacting dark matter in the form of small grains in bulk matter is proposed. Depending on the interactions with ordinary matter, dark matter grains in bulk matter may be isolated by using a centrifuge and using ordinary matter as a filter. The case of mirror matter interacting with ordinary matter via photon-mirror photon kinetic mixing provides a concrete example of this type of dark matter candidate.

  12. Nonlocal Gravity Simulates Dark Matter

    CERN Document Server

    Hehl, Friedrich W

    2008-01-01

    A nonlocal generalization of Einstein's theory of gravitation is constructed within the framework of the translational gauge theory of gravity. In the linear approximation, the nonlocal theory can be interpreted as linearized general relativity but in the presence of "dark matter" that can be simply expressed as an integral transform of matter.

  13. Dynamical Dark Matter: II. An Explicit Model

    OpenAIRE

    Dienes, Keith R.; Thomas, Brooks

    2011-01-01

    In a recent paper (arXiv:1106.4546), we introduced "dynamical dark matter," a new framework for dark-matter physics, and outlined its underlying theoretical principles and phenomenological possibilities. Unlike most traditional approaches to the dark-matter problem which hypothesize the existence of one or more stable dark-matter particles, our dynamical dark-matter framework is characterized by the fact that the requirement of stability is replaced by a delicate balancing between cosmologica...

  14. 暗物质晕和重子物质的自旋、速度剪切场及涡量的相关性分析∗%Correlation Analysis between Spin, Velocity Shear, and Vorticity of Baryonic and Dark Matter Halos

    Institute of Scientific and Technical Information of China (English)

    刘利利

    2016-01-01

    Using cosmological hydrodynamic simulations, we investigate the align-ments between velocity shear, vorticity, and the spin of dark matter halos, and study the correlation between baryonic and dark matter. We find that (1) mis-alignment between vorticity of baryonic and dark matter would develop on scales<0.2h−1 Mpc;(2) the vorticity of baryonic matter exhibits stronger alignment/anti-alignment with the eigenvectors of velocity shear than that of dark matter; (3) small/massive halos spinning parallel/perpendicular to the host filaments are sensitive to the identification of cosmic web, simulation box size, and resolution. These factors might complicate the connection between the spins of dark matter halos and galaxies, and affect the correlation signal of the alignments of galaxy spin with nearby large-scale structures.%在宇宙学流体力学模拟的基础上,通过对速度剪切场、涡量与暗物质晕自旋方向的相关性,以及重子与暗物质之间关系的研究,发现:(1)在小于0.2h−1 Mpc的尺度上,重子物质涡量与暗物质涡量的差异比较明显;(2)重子物质的涡量与速度剪切张量的相关性比暗物质要强;(3)小质量暗物质晕的自旋方向平行于其所在的纤维结构的方向,而大质量暗物质晕的自旋方向垂直于纤维结构的方向,并且这种相关性的强弱依赖于模拟盒子大小以及模拟精度.这些因素会使暗物质晕自旋与星系自旋之间的关系复杂化,也会对星系自旋方向与大尺度环境的相关性产生影响.

  15. Dark-matter 'paparazzi' exposed

    Science.gov (United States)

    Harris, Margaret

    2008-10-01

    After waiting almost two years for data that may shed light on the mysterious substance that makes up almost a quarter of the universe, some physicists thought a new result on dark matter was just too exciting to keep quiet. So when a member of the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) team recently gave a conference talk, a few audience members could not resist taking photos of the slides. By incorporating their snapshots into papers posted on the arXiv preprint server, these "paparazzi" physicists sparked a debate on both dark matter and datasharing etiquette in a digital world.

  16. DARK AND LUMINOUS MATTER IN THINGS DWARF GALAXIES

    International Nuclear Information System (INIS)

    We present mass models for the dark matter component of seven dwarf galaxies taken from 'The H I Nearby Galaxy Survey' (THINGS) and compare these with those taken from numerical Λ cold dark matter (ΛCDM) simulations. The THINGS high-resolution data significantly reduce observational uncertainties and thus allow us to derive accurate dark matter distributions in these systems. We here use the bulk velocity fields when deriving the rotation curves of the galaxies. Compared to other types of velocity fields, the bulk velocity field minimizes the effect of small-scale random motions more effectively and traces the underlying kinematics of a galaxy more properly. The 'Spitzer Infrared Nearby Galaxies Survey' 3.6 μm and ancillary optical data are used for separating the baryons from their total matter content in the galaxies. The sample dwarf galaxies are found to be dark matter dominated over most radii. The relation between total baryonic (stars + gas) mass and maximum rotation velocity of the galaxies is roughly consistent with the baryonic Tully-Fisher relation calibrated from a larger sample of gas-dominated low-mass galaxies. We find discrepancies between the derived dark matter distributions of the galaxies and those of ΛCDM simulations, even after corrections for non-circular motions have been applied. The observed solid body-like rotation curves of the galaxies rise too slowly to reflect the cusp-like dark matter distribution in cold dark matter halos. Instead, they are better described by core-like models such as pseudo-isothermal halo models dominated by a central constant-density core. The mean value of the logarithmic inner slopes of the mass density profiles is α = -0.29 ± 0.07. They are significantly different from the steep slope of ∼ - 1.0 inferred from previous dark-matter-only simulations, and are more consistent with shallower slopes found in recent ΛCDM simulations of dwarf galaxies in which the effects of baryonic feedback processes are

  17. Dark Matter and Leptogenesis Linked by Classical Scale Invariance

    CERN Document Server

    Khoze, Valentin V

    2016-01-01

    In this work we study a classically scale invariant extension of the Standard Model that can explain simultaneously dark matter and the baryon asymmetry in the universe. In our set-up we introduce a dark sector, namely a non-Abelian SU(2) hidden sector coupled to the SM via the Higgs portal, and a singlet sector responsible for generating Majorana masses for three right-handed sterile neutrinos. The gauge bosons of the dark sector are mass-degenerate and stable, and this makes them suitable as dark matter candidates. Our model also accounts for the matter-anti-matter asymmetry. The lepton flavour asymmetry is produced during CP-violating oscillations of the GeV-scale right-handed neutrinos, and converted to the baryon asymmetry by the electroweak sphalerons. All the characteristic scales in the model: the electro-weak, dark matter and the leptogenesis/neutrino mass scales, are generated radiatively, have a common origin and related to each other via scalar field couplings in perturbation theory.

  18. Influence of baryons on the spatial distribution of matter: higher order correlation functions

    Institute of Scientific and Technical Information of China (English)

    Xiao-Jun Zhu; Jun Pan

    2012-01-01

    Physical processes involving baryons could leave a non-negligible imprint on the distribution of cosmic matter.A series of simulated data sets at high resolution with identical initial conditions are employed for count-in-cell analysis,including one N-body pure dark matter run,one with only adiabatic gas and one with dissipative processes.Variances and higher order cumulants Sn of dark matter and gas are estimated.It is found that physical processes with baryons mainly affect distributions of dark matter at scales less than 1 h-1 Mpc.In comparison with the pure dark matter run,adiabatic processes alone strengthen the variance of dark matter by ~ 10% at a scale of 0.1 h-1 Mpc,while the Sn parameters of dark matter only mildly deviate by a few percent.The dissipative gas run does not differ much from the adiabatic run in terms of variance for dark matter,but renders significantly different Sn parameters describing the dark matter,bringing about a more than 10% enhancement to S3 at 0.1 h-1 Mpc and z = 0 and being even larger at a higher redshift.Distribution patterns of gas in two hydrodynamical simulations are quite different.Variance of gas at z = 0 decreases by ~ 30% in the adiabatic simulation but by ~ 60% in the nonadiabatic simulation at 0.1 h-1 Mpc.The attenuation is weaker at larger scales but is still obvious at ~ 10 h-1 Mpc.Sn parameters of gas are biased upward at scales <~ 4 h-1 Mpc,and dissipative processes show an ~ 84% promotion at z = 0 to S3 at 0.1 h-1 Mpc in contrast with the ~ 7% change in the adiabatic run.The segregation in clustering between gas and dark matter could have dramatic implications on modeling distributions of galaxies and relevant cosmological applications demanding fine details of matter distribution in a strongly nonlinear regime.

  19. From Dark Energy and Dark Matter to Dark Metric

    OpenAIRE

    Capozziello, S.; De Laurentis, M.; Francaviglia, M.; Mercadante, S

    2008-01-01

    It is nowadays clear that General Relativity cannot be the definitive theory of Gravitation due to several shortcomings that come out both from theoretical and experimental viewpoints. At large scales (astrophysical and cosmological) the attempts to match it with the latest observational data lead to invoke Dark Energy and Dark Matter as the bulk components of the cosmic fluid. Since no final evidence, at fundamental level, exists for such ingredients, it is clear that General Relativity pres...

  20. Cryogenic Dark Matter Search (CDMS): The Hunt for Dark Matter

    International Nuclear Information System (INIS)

    Deciphering the nature of dark matter has great scientific importance. A leading hypothesis is that dark matter is made of Weakly Interactive Massive Particles (WIMPs), which may result from supersymmetry or additional spatial dimensions. The underground search for elastic scattering of WIMPs on suitable targets (the so-called 'direct detection') is currently led by the Cryogenic Dark Matter Search II (CDMS II) experiment. Its sensitivity is ten times better than any other experiment and we hope to obtain another factor ten in the coming two years. After a brief recall of our recent results, I will describe the complementarity between direct detection experiments, the LHC and the ILC and I will outline the role that SLAC could play in this SuperCDMS program.