Download or read book Gamma ray Excess and the Minimal Dark Matter Model written by Michael Dürr and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simplified Dark Matter Models for the Galactic Center Gamma Ray Excess written by and published by . This book was released on 2014 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Motivated by the gamma-ray excess observed from the region surrounding the Galactic Center, we explore particle dark matter models that could potentially account for the spectrum and normalization of this signal. Taking a model-independent approach, we consider an exhaustive list of tree-level diagrams for dark matter annihilation, and determine which could account for the observed gamma-ray emission while simultaneously predicting a thermal relic abundance equal to the measured cosmological dark matter density. We identify a wide variety of models that can meet these criteria without conflicting with existing constraints from direct detection experiments or the Large Hadron Collider (LHC). The prospects for detection in near future dark matter experiments and/or the upcoming 14 TeV LHC appear quite promising.
Download or read book Searching for Dark Matter with Cosmic Gamma Rays written by Andrea Albert and published by Morgan & Claypool Publishers. This book was released on 2016-09-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Searching for Dark Matter with Cosmic Gamma Rays summarizes the evidence for dark matter and what we can learn about its particle nature using cosmic gamma rays. It has almost been 100 years since Fritz Zwicky first detected hints that most of the matter in the Universe that doesn't directly emit or reflect light. Since then, the observational evidence for dark matter has continued to grow. Dark matter may be a new kind of particle that is governed by physics beyond our Standard Model of particle physics. In many models, dark matter annihilation or decay produces gamma rays. There are a variety of instruments observing the gamma-ray sky from tens of MeV to hundreds of TeV. Some make deep, focused observations of small regions, while others provide coverage of the entire sky. Each experiment offers complementary sensitivity to dark matter searches in a variety of target sizes, locations, and dark matter mass scales. We review results from recent gamma-ray experiments including anomalies some have attributed to dark matter. We also discuss how our gamma-ray observations complement other dark matter searches and the prospects for future experiments.
Download or read book Hidden Sector Dark Matter Models for the Galactic Center Gamma Ray Excess written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The gamma-ray excess observed from the Galactic Center can be interpreted as dark matter particles annihilating into Standard Model fermions with a cross section near that expected for a thermal relic. Although many particle physics models have been shown to be able to account for this signal, the fact that this particle has not yet been observed in direct detection experiments somewhat restricts the nature of its interactions. One way to suppress the dark matter's elastic scattering cross section with nuclei is to consider models in which the dark matter is part of a hidden sector. In such models, the dark matter can annihilate into other hidden sector particles, which then decay into Standard Model fermions through a small degree of mixing with the photon, Z, or Higgs bosons. After discussing the gamma-ray signal from hidden sector dark matter in general terms, we consider two concrete realizations: a hidden photon model in which the dark matter annihilates into a pair of vector gauge bosons that decay through kinetic mixing with the photon, and a scenario within the generalized NMSSM in which the dark matter is a singlino-like neutralino that annihilates into a pair of singlet Higgs bosons, which decay through their mixing with the Higgs bosons of the MSSM.
Download or read book Flavored Dark Matter and the Galactic Center Gamma Ray Excess written by and published by . This book was released on 2014 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal relic dark matter particles with a mass of 31-40 GeV and that dominantly annihilate to bottom quarks have been shown to provide an excellent description of the excess gamma rays observed from the center of the Milky Way. Flavored dark matter provides a well-motivated framework in which the dark matter can dominantly couple to bottom quarks in a flavor-safe manner. We propose a phenomenologically viable model of bottom flavored dark matter that can account for the spectral shape and normalization of the gamma-ray excess while naturally suppressing the elastic scattering cross sections probed by direct detection experiments. This model will be definitively tested with increased exposure at LUX and with data from the upcoming high-energy run of the Large Hadron Collider (LHC).
Download or read book The Characterization of the Gamma Ray Signal from the Central Milky Way written by and published by . This book was released on 2014 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Past studies have identified a spatially extended excess of ~1-3 GeV gamma rays from the region surrounding the Galactic Center, consistent with the emission expected from annihilating dark matter. We revisit and scrutinize this signal with the intention of further constraining its characteristics and origin. By applying cuts to the Fermi event parameter CTBCORE, we suppress the tails of the point spread function and generate high resolution gamma-ray maps, enabling us to more easily separate the various gamma-ray components. Within these maps, we find the GeV excess to be robust and highly statistically significant, with a spectrum, angular distribution, and overall normalization that is in good agreement with that predicted by simple annihilating dark matter models. For example, the signal is very well fit by a 31-40 GeV dark matter particle annihilating to b quarks with an annihilation cross section of sigma v = (1.4-2.0) x 10^-26 cm^3/s (normalized to a local dark matter density of 0.3 GeV/cm^3). Furthermore, we confirm that the angular distribution of the excess is approximately spherically symmetric and centered around the dynamical center of the Milky Way (within ~0.05 degrees of Sgr A*), showing no sign of elongation along or perpendicular to the Galactic Plane. The signal is observed to extend to at least 10 degrees from the Galactic Center, disfavoring the possibility that this emission originates from millisecond pulsars.
Download or read book Supersymmetric Sub Electroweak Scale Dark Matter the Galactic Center Gamma ray Excess and Exotic Decays of the 125 GeV Higgs Boson written by and published by . This book was released on 2014 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Is The Gamma Ray Source 3FGL J2212 5 0703 A Dark Matter Subhalo written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In a previous paper, we pointed out that the gamma-ray source 3FGL J2212.5+0703 shows evidence of being spatially extended. If a gamma-ray source without detectable emission at other wavelengths were unambiguously determined to be spatially extended, it could not be explained by known astrophysics, and would constitute a smoking gun for dark matter particles annihilating in a nearby subhalo. With this prospect in mind, we scrutinize the gamma-ray emission from this source, finding that it prefers a spatially extended profile over that of a single point-like source with 5.1 sigma statistical significance. We also use a large sample of active galactic nuclei and other known gamma-rays sources as a control group, confirming, as expected, that statistically significant extension is rare among such objects. We argue that the most likely (non-dark matter) explanation for this apparent extension is a pair of bright gamma-ray sources that serendipitously lie very close to each other, and estimate that there is a chance probability of ~2% that such a pair would exist somewhere on the sky. In the case of 3FGL J2212.5+0703, a model with a second gamma-ray point source at the location of a known BZCAT/CRATES radio source yields fits that are comparable in quality to those obtained for a single extended source. If 3FGL J2212.5+0703 is a dark matter subhalo, it would imply that dark matter particles have a mass of ~18-33 GeV and an annihilation cross section on the order of sigma v ~ 10^-26 cm^3/s (for the representative case of annihilations to bb), similar to the values required to generate the Galactic Center gamma-ray excess.
Download or read book Electroweak Interacting Spin 1 Dark Matter and Its Phenomenology written by Motoko Fujiwara and published by Springer Nature. This book was released on 2023-05-05 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers construction of a renormalizable effective theory of electroweak-interacting spin-1 dark matter (DM). The effective theory realizes minimal but essential features of DM predicted in extra-dimension models, and enables to systematically treat non-perturbative corrections such as the Sommerfeld effects. Deriving an annihilation cross section including the Sommerfeld effects based on the effective theory, the author discusses the future sensitivity of observations to gamma-ray from the Galactic Center. As a result, the author explains the monochromatic gamma-ray signatures originate from two photons (γγ) or photon and Z boson (γZ) produced in the process of DM annihilations, and concludes a possible scenario that unstable neutral spin-1 particles (Z’) appear and results in a spectral peak in addition to the one caused by γγ and γZ channels in gamma-ray observations. If those two spectral peaks are observed, the masses of spin-1 DM and Z’ would be reconstructed.
Download or read book Searching for Dark Matter with Cosmic Gamma Rays written by A Albert and published by Myprint. This book was released on 2016-09-06 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gamma Ray Lines from a Universal Extra Dimension written by and published by . This book was released on 2012 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Indirect Dark Matter searches are based on the observation of secondary particles produced by the annihilation or decay of Dark Matter. Among them, gamma-rays are perhaps the most promising messengers, as they do not suffer deflection or absorption on Galactic scales, so their observation would directly reveal the position and the energy spectrum of the emitting source. Here, we study the detailed gamma-ray energy spectrum of Kaluza--Klein Dark Matter in a theory with 5 Universal Extra Dimensions. We focus in particular on the two body annihilation of Dark Matter particles into a photon and another particle, which produces monochromatic photons, resulting in a line in the energy spectrum of gamma rays. Previous calculations in the context of the five dimensional UED model have computed the line signal from annihilations into \gamma \gamma, but we extend these results to include \gamma Z and \gamma H final states. We find that these spectral lines are subdominant compared to the predicted \gamma \gamma signal, but they would be important as follow-up signals in the event of the observation of the \gamma \gamma line, in order to distinguish the 5d UED model from other theoretical scenarios.
Download or read book An Introduction to Particle Dark Matter written by Stefano Profumo and published by Wspc (Europe). This book was released on 2017 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle dark matter: the name of the game -- The thermal relic paradigm: zeroth-order lessons from cosmology -- The thermal relic paradigm: a closer look -- The art of WIMP direct detection -- Indirect dark matter searches -- Searching for dark matter with particle colliders -- Axions and axion-like particles as dark matter -- Sterile neutrinos as dark matter particles -- Bestiarium: a short, biased compendium of notable dark matter particle candidates and models
Download or read book Particle Dark Matter written by Gianfranco Bertone and published by Cambridge University Press. This book was released on 2010-01-07 with total page 763 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the dark matter problem in particle physics, astrophysics and cosmology for graduate students and researchers.
Download or read book Constraining TeV scale Astrophysical Foregrounds for Dark Matter Searches with HAWC written by Mehr Un Nisa and published by . This book was released on 2019 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Astrophysical observations are central to the quest for new physics including the search for dark matter. The search is based on identifying potential deviations from the Standard Model in the cosmic-ray and the electromagnetic spectrum of astrophysical sources. The deviations could either be signatures of dark matter or have consequences for our understanding of known sources. The last decade of precision measurements from detectors in space, such as the Fermi Gamma-ray Space Telescope, and the Alpha Magnetic Spectrometer for detecting cosmic rays aboard the International Space Station, have identified certain "anomalies" or unexpected spectral features, that challenge the standard models of how cosmic rays are produced and propagate through the Galaxy. Examples include an unexpectedly hard spectrum of cosmic-ray antiprotons at energies above a few hundred GeV, and an unexplained excess of very-high-energy gamma rays from the Sun. An excess of cosmic-ray antiprotons and a hard spectrum of gamma rays from the Sun also feature in the predictions of various models of dark matter annihilation. However, without a complete understanding of the antiproton spectrum, and the production mechanisms of solar gamma rays, it is impossible to differentiate new physics from the standard astrophysical foreground flux of these particles. Measuring these fluxes at energies that extend into the TeV range is an observational challenge that we explore in this thesis. The High AltitudeWater Cherenkov (HAWC) Observatory is a wide field-of-view array that is currently the only detector capable of making high-statistics measurements of cosmic rays and gamma rays at multi-TeV energies. This work uses data from HAWC collected between 2014-2017 to constrain two unique fluxes at the TeV scale: antiprotons in Galactic cosmic rays, and gamma rays from the quiescent Sun - both relevant foregrounds for astrophysical searches for physics beyond the Standard Model. Cosmic rays in the inner solar system are subject to deflection by the magnetic fields of the Earth and the Sun, affecting the observed deficit or "shadow" of the Moon/Sun. Cosmic rays also interact with the Sun's atmosphere to produce a steady emission of gamma rays up to at least 200 GeV, though the exact underlying mechanism remains a puzzle. We present the strongest upper limits on the antiproton to proton ratio in TeV cosmic rays at ~1% using the Moon shadow as a momentum/ charge discriminant. We also discuss our search for excess gamma rays from the Sun above 1 TeV, and present the resulting implications for models of dark matter capture and annihilation in the Sun. Our results constrain the steady gamma-ray emission from the Sun up to a few times 10−12 TeV cm−2 s−1 at 1 TeV. For dark matter annihilation with long-lived mediators in the Sun, we present the strongest upper limits on dark matter-proton scattering cross section up to ~10−45 cm2, which is a potential improvement of four orders of magnitude compared to direct-detection experiments for dark matter mass of 1 TeV."--Pages xi-xii.
Download or read book Dark Matter Signals written by Samuel Joseph Witte and published by . This book was released on 2017 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: A vast number of independent astrophysical and cosmological observations suggest that the dominant form of matter in the Universe, known as dark matter, is neither luminous nor baryonic. Despite nearly half a decade of research, the non-gravitational nature of dark matter, if any, remains a mystery. Motivated primarily by preferred theoretical extensions of the Standard Model and a relatively simple production mechanism, the weakly interacting massive particle (WIMP) has long been considered to be among the most appealing dark matter particle candidates. This dissertation is comprised of largely independent works that focus on understanding and constraining various signals that could arise from WIMP dark matter. Specifically, Chapters 2 and 3 address the impact that non-standard astrophysics and particle physics could have on the observed scattering rate in direct dark matter detection experiments; Chapter 4 presents a halo-dependent and an halo-independent update on the viability of a dark matter interpretation of the CDMS-II-Si data; Chapter 5 generalizes the halo-independent analysis formalism such that the compatibility of multiple experiments can be assessed, and the preferred halo-independent parameter space can be identified, for global likelihoods comprised of at least one extended likelihood; Chapter 6 discusses the prospects for detecting gamma-rays from dark matter annihilating in local dark matter subahlos; Chapter 7 presents updated constraints on simplified dark matter models that are consistent with the Galactic Center excess; and Chapter 8 discusses the extent to which future direct detection experiments may be able to elucidate the high-energy dark matter theory from observations of low-energy nuclear recoils.
Download or read book Aspects of WIMP Dark Matter Searches at Colliders and Other Probes written by Enrico Morgante and published by Springer. This book was released on 2017-10-05 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis covers several theoretical aspects of WIMP (weakly interacting massive particles) dark matter searches, with a particular emphasis on colliders. It mainly focuses on the use of effective field theories as a tool for Large Hadron Collider (LHC) searches, discussing in detail the issue of their validity, and on simplified dark matter models, which are receiving a growing attention from the physics community. It highlights the theoretical consistency of simplified models, which is essential in order to correctly exploit their potential and for them to be a common reference when comparing results from different experiments. This thesis is of interest to researchers (both theorists and experimentalists) in the field of dark matter searches, and offers a comprehensive introduction to dark matter and to WIMP searches for students and non-experts.
Download or read book Dark Matter Searches with Gamma Rays from the Galactic Center Halo and Cosmic Ray Antimatter written by James Lee Ryan and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is unknown what constitutes dark matter.The properties of dark matter particles may be observed indirectly if dark matter annihilates or decays into Standard Model particles that are then detected. Work is presented on two such experiments, performed with GAPS and VERITAS. GAPS is a forthcoming balloon-borne cosmic-ray antimatter detector whose unprecedented sensitivity to the fluxes of antiprotons, antideuterons, and antihelium makes possible the detection of a variety of exotic sources of these particles. We outline development of the GAPS TOF system, and demonstrate its ability to achieve desired resolutions in time, position, and energy. VERITAS is an imaging atmospheric Cherenkov telescope array that has been observing gamma rays from the Galactic Center region for over 10 years. We develop a template-based background estimation method to look for excess gamma rays in the Galactic Center halo. No significant excess is found, and limits on the thermally-averaged annihilation cross section are derived with dependence on the annihilation channel, reaching $\langle \sigma_\text{ann} v\rangle
