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Download or read book Time-dependent Models for Dark Matter at the Galactic Center written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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ISBN 13 :
Total Pages : 36 pages
Book Rating : 4.:/5 (16 download)
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 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.
Author : F. Bakalian
Publisher : The VLS Research Foundation
ISBN 13 :
Total Pages : 200 pages
Book Rating : 4./5 ( download)
Download or read book A new standard model of cosmology: Time-varying fundamental constants and the evolution of the universe written by F. Bakalian and published by The VLS Research Foundation. This book was released on 2024-01-01 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new theoretical framework is presented to explain the evolution of the universe based on the time-varying properties of the fundamental constants. A static universe with time-varying constants can explain the origin of the cosmic microwave background radiation, CMB anisotropies, the CMB cold spot, the observed redshift-distance modulus data, the origin and composition of dark matter in the universe, galaxy cluster mass estimates, Milky Way galaxy luminosity estimates, population II stellar properties, vacuum-photon interactions, energy cycling between matter, radiation and vacuum field components, time-varying Higgs mechanism and particle mass, and the observed matter-antimatter dichotomy. This is a complete theoretical framework that explains the observable universe and resolves many of the issues with modern-day cosmology.
Author : Gianfranco Bertone
Publisher : Cambridge University Press
ISBN 13 : 0521763681
Total Pages : 763 pages
Book Rating : 4.5/5 (217 download)
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.
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ISBN 13 :
Total Pages : 165 pages
Book Rating : 4.:/5 (953 download)
Download or read book Dark Matter Annihilation at the Galactic Center written by and published by . This book was released on 2013 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 role of future telescopes in di erentiating a dark matter model from astrophysical emission.
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ISBN 13 :
Total Pages : 13 pages
Book Rating : 4.:/5 (727 download)
Download or read book Relativistic Dark Matter at the Galactic Center written by and published by . This book was released on 2007 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a large region of the supersymmetry parameter space, the annihilation cross section for neutralino dark matter is strongly dependent on the relative velocity of the incoming particles. We explore the consequences of this velocity dependence in the context of indirect detection of dark matter from the galactic center. We find that the increase in the annihilation cross section at high velocities leads to a flattening of the halo density profile near the galactic center and an enhancement of the annihilation signal.
Author : John N. Bahcall
Publisher : World Scientific
ISBN 13 : 9812567186
Total Pages : 246 pages
Book Rating : 4.8/5 (125 download)
Download or read book Dark Matter in the Universe written by John N. Bahcall and published by World Scientific. This book was released on 2004 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: If standard gravitational theory is correct, then most of the matterin the universe is in an unidentified form which does not emit enoughlight to have been detected by current instrumentation. This book isthe second editon of the lectures given at the 4th Jerusalem WinterSchool for Theoretical Physics, with new material added. The lecturesare devoted to the missing matter problem in the universe, thesearch to understand dark matter. The goal of this volume is to makecurrent research work on unseen matter accessible to students withoutprior experience in this area and to provide insights for experts inrelated research fields. Due to the pedagogical nature of the originallectures and the intense discussions between the lecturers and thestudents, the written lectures included in this volume often containtechniques and explanations not found in more formal journalpublications.
Author : Società italiana di fisica
Publisher : IOS Press
ISBN 13 : 1614992177
Total Pages : 739 pages
Book Rating : 4.6/5 (149 download)
Download or read book Dark Matter in the Universe written by Società italiana di fisica and published by IOS Press. This book was released on 1996 with total page 739 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics and astrophysics came to dark matter through many different routes, finally accepting it, but often with some distaste. It has been noticed that the existence of dark matter is yet another displacement of humans from the centre of the Universe: not only do our planet and our sun have no central position in the Universe, not only are humans just animals (although with a 'specialized' central nervous system), but even the material of which we are made is only a marginal component of the cosmic substance! If this is the right attitude to take, scientists feeling distaste for dark matter are much like Galileo Galilei's colleagues who refused to look through the telescope to watch the Medici planets. Nevertheless, astronomers, when required to take a ballot in favour of some cosmological model, often still vote for 'pure baryonic' with substantial majorities, although most cosmologists assume that a 'cold' component of dark matter plays a role in producing the world as we observe it. Among the many subjects covered by the book, particular emphasis was given to 1) summarizing the current status of the observations both of the distribution of the nearby galaxies and of the evolution of more distant galaxies; 2) advanced statistical techniques for quantifying structure in galaxy redshift and peculiar velocity surveys; 3) the art of cosmic inflation and models for dark matter candidates, and their implications for cosmic microwave background observations; 4) implications of cold dark matter variants for large scale structure, as worked out both by quasi-linear techniques and by fully nonlinear simulations; and 5) Eulerian and Lagrangian approximations for treating the nonlinear dynamics.
Author : J. Val Blain
Publisher : Nova Publishers
ISBN 13 : 9781594542435
Total Pages : 272 pages
Book Rating : 4.5/5 (424 download)
Download or read book Progress in Dark Matter Research written by J. Val Blain and published by Nova Publishers. This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is generally believed that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the cosmic microwave background enough to form the large-scale structures that we see in the universe today. For each of the stellar, galactic, and galaxy cluster/supercluster observations the basic principle is that if we measure velocities in some region, then there has to be enough mass there for gravity to stop all the objects flying apart. Dark matter has important consequences for the evolution of the Universe and the structure within it. According to general relativity, the Universe must conform to one of three possible types: open, flat, or closed. The total amount of mass and energy in the universe determines which of the three possibilities applies to the Universe. In the case of an open Universe, the total mass and energy density (denoted by the Greek letter Omega) is less than unity. If the Universe is closed, Omega is greater than unity. For the case where Omega is exactly equal to one the Universe is "flat". This book details leading-edge research from around the globe.
Author : Scott Dodelson
Publisher : Academic Press
ISBN 13 : 0122191412
Total Pages : 462 pages
Book Rating : 4.1/5 (221 download)
Download or read book Modern Cosmology written by Scott Dodelson and published by Academic Press. This book was released on 2003-03-13 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced text for senior undergraduates, graduate students and physical scientists in fields outside cosmology. This is a self-contained book focusing on the linear theory of the evolution of density perturbations in the universe, and the anisotropiesin the cosmic microwave background.
Author : Jeremie Choquette
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (111 download)
Download or read book Self-interacting Dark Matter written by Jeremie Choquette and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Self-interacting dark matter models have grown in influence over the last decade as an alternative to cold dark matter, resolving key problems in the distribution of dark matter structure on sub-galactic scales. In this manuscript-based thesis, we present four papers related to dark matter astrophysics, with an emphasis on self-interacting dark matter. In the first, we consider a dark sector in which a hidden SU(2) gauge symmetry, which breaks to U(1) via a Higgs-like doublet, results in a nonabelian model of atomic dark matter. The model has an interesting phenomenology and can result in the correct relic density. In the second and third papers, we explore a potential signal from annihilating dark matter in the Galactic Center. It has been claimed that the Galactic Center excess is at odds with observations of dwarf spheroidal galaxies that show no signal, however we present two scenarios in which the signal from dwarf galaxies would be diminished by a sufficient margin to alleviate the tension. In the first, the dark matter annihilates with a velocity dependent cross section, decreasing the annihilation rate in dwarf galaxies. In the second, we consider the fact that dwarf spheroidal galaxies likely have density profiles which have a central core of near-constant density (rather than a centrally peaked or 'cuspy' profile), and show that density profiles consistent with self-interacting dark matter as well as observed density profiles would weaken the signal to undetectable levels. In the fourth paper, we explore the formation of high-redshift supermassive black holes from two-component dark matter models, determining the self-interaction cross section and self-interacting dark matter fraction required to provide an alternative explanation to the observed early formation of supermassive black holes." --
Author : Oleg Y. Gnedin
Publisher :
ISBN 13 :
Total Pages : 4 pages
Book Rating : 4.:/5 (122 download)
Download or read book Dark Matter Profile in the Galactic Center written by Oleg Y. Gnedin and published by . This book was released on 2004 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a quasiequilibrium profile of dark matter particles in the inner parsec of the Galaxy, dmr-3/2. This 'minicusp' profile is caused by scattering with the dense stellar cluster around the supermassive black hole in Sgr A* and is independent of the initial conditions. The implications for detection of gamma rays from annihilation of weakly interacting massive dark matter particle in the Galactic center are a mild enhancement of the flux and a characteristic central feature in the angular distribution which could be detectable by high-resolution atmospheric Cherenkov telescopes.
Author :
Publisher :
ISBN 13 :
Total Pages : 322 pages
Book Rating : 4.:/5 (659 download)
Download or read book Dark Matter: Origin, Detection, and Collider Implications written by and published by . This book was released on 2009 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmological observations have precisely measured the amount of cold dark matter (CDM) in the Universe. The best fit value corresponds to around 23% of the Universe being composed of CDM. Nothing in the Standard Model (SM) is able to account for this cold dark matter. This provides unambiguous evidence for physics beyond the SM. From particle physics, the hierarchy between the electroweak and Planck scales within the SM provides motivation to consider new physics beyond the SM. In this thesis, I investigated the origin of CDM, analyzed various prospects for indirect detection, and studied its collider implications. We focused on two such models: the Left Right Twin Higgs (LRTH) model and the Inert Doublet model (IDM). Both of these models contain a neutral scalar that is stable and a good CDM candidate. We performed a CDM analysis, and identified regions of parameter space that can account for all of the CDM in the Universe. CDM can become trapped around massive objects such as the Sun, Earth, and galactic center. Over time, these CDM particles can annihilate to produce neutrinos and photons. Within the IDM framework, we analyzed the neutrino signal from the Sun and Earth and the photon signal from the galactic center. Due to the nature of new particles within the IDM, there are implications for signals at high energy colliders, such as the Large Hadron Collider (LHC). These particles are produced and can subsequently decay to CDM, jets, and leptons. Within the framework of the IDM, we performed a dilepton signal analysis at the LHC. There exists a synergy between particle physics and cosmology. The study of the interplay between these two fields could provide valuable insights and bring a better understanding of Nature within our grasp. It is an exciting time for physics.
Author : Grace Dupuis
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (979 download)
Download or read book Model-dependent Collider Signatures of Particle Dark Matter written by Grace Dupuis and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The identity and nature of dark matter (DM) is one of the most important open questions in physics. The idea that dark matter is some exotic particle species is a leading hypothesis, and is strongly supported by cosmological data that favours non-baryonic particle dark matter. Although the Standard Model (SM) of particle physics has been extremely successful in describing observed phenomena, the absence of a DM candidate, in addition to many other unresolved questions, motivates the search for new physics. This thesis presents a study constraining new physics beyond the SM with experimental results, primarily from the Large Hadron Collider (LHC), in several models that are motivated by providing candidates for particle dark matter. The following models and their associated collider signatures are investigated. A Z′ model, in which the extra U(1)′ gauge group is kinetically mixed with the SM hypercharge is first considered. The experimental limits from dilepton production are used to constrain the Z′ mass and kinetic mixing parameter. Contributions of the invisible Z′ decay width are used to further constrain the model parameter space. Next, the production of new coloured fermionic mediators is investigated in a model of scalar, flavoured dark matter. Experimental results from signals characterized by final state jets and missing transverse energy, resulting from mediator pair production and subsequent decay to a quark and the dark matter particle, are used to constrain the mediator mass. A Higgs portal model is also considered, with the addition of a scalar singlet field that mixes with the SM Higgs. The constraints from current LHC Higgs data are established, and prospective signatures at the proposed International Linear Collider (ILC) are investigated; the discovery potential in the remaining allowed parameter space is explored, through precision measurement in double Higgs production. Finally, a scalar extension is also applied to a DM model with two additional scalar mediators, in a model that is motivated by the galactic centre (GC) gamma ray excess seen in data from the Fermi Large Area Telescope. Results from LHC Higgs searches and measurements are used to constrain the scalar parameters in a benchmark model that was fit to the GC excess." --
Author : John N Bahcall
Publisher : World Scientific
ISBN 13 : 9814482714
Total Pages : 246 pages
Book Rating : 4.8/5 (144 download)
Download or read book Dark Matter In The Universe (Second Edition) - 4th Jerusalem Winter School For Theoretical Physics Lectures written by John N Bahcall and published by World Scientific. This book was released on 2004-09-03 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: If standard gravitational theory is correct, then most of the matter in the universe is in an unidentified form which does not emit enough light to have been detected by current instrumentation. This book is the second editon of the lectures given at the 4th Jerusalem Winter School for Theoretical Physics, with new material added. The lectures are devoted to the “missing matter” problem in the universe, the search to understand dark matter. The goal of this volume is to make current research work on unseen matter accessible to students without prior experience in this area and to provide insights for experts in related research fields. Due to the pedagogical nature of the original lectures and the intense discussions between the lecturers and the students, the written lectures included in this volume often contain techniques and explanations not found in more formal journal publications.
Author : Tanushree Basak
Publisher : Morgan & Claypool Publishers
ISBN 13 : 1643271326
Total Pages : 63 pages
Book Rating : 4.6/5 (432 download)
Download or read book An Approach to Dark Matter Modelling written by Tanushree Basak and published by Morgan & Claypool Publishers. This book was released on 2018-09-05 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the field of particle and astrophysics, one of the major unresolved problems is to understand the nature and properties of dark matter, which constitutes almost 80% of the matter content of the universe. This book gives a pedagogical introduction to the field of dark matter in general, and in particular to the model building perspective. Starting from the evidence and need for dark matter, it goes into the deeper understanding of how to accommodate a dark matter candidate in a particle physics model. This book focuses on teaching the basic tools for model building of dark matter, starting from the easiest to gradually the difficult one. Although there are plenty of dark matter models available in the literature, this book concentrates on the important ones. This book aims to motivate the reader to propose a new dark matter model complying with all observational constraints.
