The standard model of modern cosmology is unthinkable without dark matter, although direct detections are still missing. A broad perspective how matter was postulated and became accepted presented, from prehistory, over observations galaxy clusters, rotation curves, the search for baryonic possible alternative explanations via modified gravity, up to hunt particles. interplay described between observational discoveries theoretical arguments which led finally adoption this paradigm.

We analyze the first two years of data from Fermi Gamma Ray Space Telescope direction inner 10 degrees around Galactic Center with intention constraining, or finding evidence of, annihilating dark matter. find that morphology and spectrum emission between 1.25 is well described by a processes decaying pions produced in cosmic ray collisions gas, inverse Compton scattering electrons both disk bulge Inner Galaxy, along gamma rays known points sources region. The observed within approximately...

The region surrounding the center of Milky Way is both astrophysically rich and complex, predicted to contain very high densities dark matter. Utilizing three years data from Fermi Gamma Ray Space Telescope (and recently available Pass 7 ultraclean event class), we study morphology spectrum gamma ray emission this find evidence a spatially extended component which peaks at energies between 300 MeV 10 GeV. We compare our results those reported by other groups good agreement. could potentially...

We discuss the possibility that recent detection of 511 keV $\ensuremath{\gamma}$ rays from galactic bulge, as observed by INTEGRAL, is a consequence low mass ($1--100\text{ }\mathrm{MeV}$) particle dark matter annihilations. type halo profile favored observations well size annihilation cross section needed to account for signal. find such scenario consistent with relic density and other constraints astrophysics physics.

We study the variation of spectrum Fermi Bubbles with Galactic latitude. Far from plane (|b|≳ 30°), observed gamma-ray emission is nearly invariant latitude, and consistent arising inverse Compton scattering interstellar radiation field by cosmic-ray electrons an approximately power-law spectrum. The same in presence microgauss-scale magnetic fields can also generate microwave "haze". At lower latitudes (|b|≲ 20°), contrast, correlated possesses a pronounced spectral feature peaking at ∼1–4...

We study the gamma rays observed by Fermi Gamma Ray Space Telescope from direction of Galactic Center and find that their angular distribution energy spectrum are well described a dark matter annihilation scenario. In particular, we good fit to data for particles with 25-30 GeV mass, an cross section ~9x10^-26 cm^3/s, distributed cusped halo profile within inner kiloparsec Galaxy. cannot, however, exclude possibility these photons originate astrophysical source or sources similar morphology...

The AMS experiment onboard the International Space Station has recently provided cosmic ray electron and positron data with unprecedented precision in range from 0.5 to 350 GeV. observed rise fraction at energies above 10 GeV remains unexplained, proposed solutions ranging local pulsars TeV-scale dark matter. Here, we make use of this high quality place stringent limits on matter masses below ~300 GeV, annihilating or decaying leptonic final states, essentially independent origin rise. We...

Motivated by the gamma-ray excess observed from region surrounding Galactic Center, we explore particle dark matter models that could potentially account for spectrum and normalization of this signal. Taking a model-independent approach, consider an exhaustive list tree-level diagrams annihilation, determine which emission while simultaneously predicting thermal relic abundance equal to measured cosmological density. We identify wide variety can meet these criteria without conflicting with...

The EDGES Collaboration has recently reported the detection of a stronger-than-expected absorption feature in global 21-cm spectrum, centered at frequency corresponding to redshift z≃17. This observation been interpreted as evidence that gas was cooled during this era result scattering with dark matter. In Letter, we explore possibility, applying constraints from cosmic microwave background, light element abundances, Supernova 1987A, and variety laboratory experiments. After taking these...

In this paper, we explore in detail the cosmological implications of an abelian $L_\mu-L_\tau$ gauge extension Standard Model featuring a light and weakly coupled $Z'$. Such scenario is motivated by longstanding $\sim \, 4 \sigma$ discrepancy between measured predicted values muon's anomalous magnetic moment, $(g-2)_\mu$, as well tension late early time determinations Hubble constant. If sufficiently light, $Z'$ population will decay to neutrinos, increasing overall energy density radiation...

In recent years, direct detection, indirect and collider experiments have placed increasingly stringent constraints on particle dark matter, exploring much of the parameter space associated with WIMP paradigm. this paper, we focus subset models in which matter annihilates early universe through couplings to either Standard Model Z or Higgs boson. Considering fermionic, scalar, vector candidates within a model-independent context, find that overwhelming majority these are already ruled out by...

A bstract If even a relatively small number of black holes were created in the early universe, they will constitute an increasingly large fraction total energy density as space expands. It is thus well-motivated to consider scenarios which universe included era primordial dominated density. Within this context, we Hawking radiation mechanism produce both dark and matter. hole era, find that at level Δ N eff ∼ 0 . 03 − 2 for each light decoupled species spin 0, 1/2, or 1. This range well...

Abstract There is controversy surrounding the origin and evolution of our universe's largest supermassive black holes (SMBHs). In this study, we consider possibility that some these formed from direct collapse primordial density perturbations. Since mass a hole limited by size cosmological horizon at time collapse, SMBHs must form rather late, are naively in conflict with constraints CMB spectral distortions. These limits can be avoided, however, if distribution curvature perturbations...

This is a review of neutrino astronomy anchored to the observational fact that Nature accelerates protons and photons energies in excess $10^{20}$ $10^{13}$ eV, respectively. Although discovery cosmic rays dates back close century, we do not know how where they are accelerated. Basic elementary-particle physics dictates universal upper limit on their energy $5\times10^{19}$ so-called Greisen-Kuzmin-Zatsepin cutoff; however, particles this have been observed by all experiments, adding one...

Assuming that dark matter is a weakly interacting massive particle (WIMP) species X produced in the early Universe as cold thermal relic, we study collider signal of pp or $ p\bar{p} \rightarrow \bar{X}X + jets and its distinguishability from standard-model background processes associated with missing energy. We assume WIMP sole related to within reach LHC — "maverick" it couples quarks through higher dimensional contact interaction. simulate final-state X\bar{X} dominant (SM) find...

We discuss the prospects for next generation neutrino telescopes, such as IceCube, to measure flavor ratios of high-energy astrophysical neutrinos. The expected at sources are ${\ensuremath{\varphi}}_{{\ensuremath{\nu}}_{e}}:{\ensuremath{\varphi}}_{{\ensuremath{\nu}}_{\ensuremath{\mu}}}:{\ensuremath{\varphi}}_{{\ensuremath{\nu}}_{\ensuremath{\tau}}}=1:2:0,$ and oscillations quickly transform these $1:1:1.$ can be deduced from relative rates showers $({\ensuremath{\nu}}_{e}$ charged current,...

The Wilkinson Microwave Anisotropy Probe (WMAP) experiment has revealed an excess of microwave emission from the region around center our Galaxy. It been suggested that this signal, known as ``WMAP haze,'' could be synchrotron relativistic electrons and positrons generated in dark matter annihilations. In article, we revisit possibility. We find angular distribution WMAP haze matches prediction for annihilations with a cusped density profile,...

Very high energy gamma rays are expected to be absorbed by the extragalactic background light over cosmological distances via process of electron-positron pair production. Recent observations cosmologically distant gamma-ray emitters ground based telescopes have, however, revealed a surprising degree transparency universe very photons. One possible mechanism explain this observation is oscillation between photons and axionlike particles (ALPs). Here we explore possibility further, focusing...

Neutralino dark matter is generally assumed to be relatively heavy, with a mass near the electroweak scale. This does not necessarily need case, however. In next-to-minimal supersymmetric standard model (NMSSM) and other models an extended Higgs sector, very light $CP$-odd boson can naturally arise making it possible for neutralino annihilate efficiently enough avoid being overproduced in early Universe. this article, we explore characteristics of needed include neutralino, $100\text{...

The rise of the cosmic ray positron fraction with energy, as first observed high confidence by PAMELA, implies that a large flux energy positrons has been recently (or is being currently) injected into local volume Milky Way. With new and much more precise measurement provided AMS, we revisit question origin these positrons. We find while some dark matter models (annihilating directly to electrons or muons) no longer appear be capable accommodating data, other in which ~1-3 TeV particles...

Despite compelling arguments that significant discoveries of physics beyond the standard model are likely to be made at Large Hadron Collider, it remains possible this machine will make no such discoveries, or directly relevant dark matter problem. In article, we study ability astrophysical experiments deduce nature in a scenario. most studies, relic abundance and detection prospects evaluated within context some specific particle models (e.g., supersymmetry). Here, assuming single weakly...

Using data from the Fermi Gamma-Ray Space Telescope, a spatially extended component of gamma rays has been identified direction Galactic Center, peaking at energies ~2-3 GeV. More recently, it shown that this signal is not confined to innermost hundreds parsecs Galaxy, but instead extends least ~3 kpc Center. While spectrum, intensity, and angular distribution in good agreement with predictions annihilating dark matter, also suggested population unresolved millisecond pulsars could be...