Indirect Search for Dark Matter by Measurements of the Cosmic Ray Positron Spectrum with the AMS 02 Experiment PDF Download

Author: Paolo Maestro
Publisher:
ISBN:
Category :
Languages : en
Pages : 113

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Author: Elisa Falchini
Publisher:
ISBN:
Category :
Languages : en
Pages : 124

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Author: Gaelle Giesen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Overwhelming evidence for the existence of Dark Matter (DM), in the form of an unknownparticle filling the galactic halos, originates from many observations in astrophysics and cosmology: its gravitational effects are apparent on galactic rotations, in galaxy clusters and in shaping the large scale structure of the Universe. On the other hand, a non-gravitational manifestation of its presence is yet to be unveiled. One of the most promising techniques is the one of indirect detection, aimed at identifying excesses in cosmic ray fluxes which could possibly be produced by DM annihilations or decays in the Milky Way halo. The current experimental efforts mainly focus in the GeV to TeV energy range, which is also where signals from WIMPs (Weakly Interacting Massive Particles) are expected. Focussing on charged cosmic rays, in particular antiprotons, electrons and positrons, as well as their secondary emissions, an analysis of current and forseen cosmic ray measurements and improvements on astrophysical models are presented. Antiproton data from PAMELA imposes contraints on annihilating and decaying DM which are similar to (or even slightly stronger than) the most stringent bounds from gamma ray experiments, even when kinetic energies below 10 GeV are discarded. However, choosing different sets of astrophysical parameters, in the form of propagation models and halo profiles, allows the contraints to span over one or two orders of magnitude. In order to exploit fully the power of antiprotons to constrain or discover DM, effects which were previously perceived as subleading turn out to be relevant especially for the analysis of the newly released AMS-02 data. In fact, including energy losses, diffusive reaccelleration and solar modulation can somewhat modify the current bounds, even at large DM masses. A wrong interpretation of the data may arise if they are not taken into account. Finally, using the updated proton and helium fluxes just released by the AMS-02 experiment, the astrophysical antiproton to proton ratio and its uncertainties are reevaluated and compared to the preliminarly reported AMS-02 measurements. No unambiguous evidence for a significant excess with respect to expectations is found. Yet, some preference for thicker halos and a flatter energy dependence of the diffusion coefficient starts to emerge. New stringed constraints on DM annihilation and decay are derived. Secondary emissions from electrons and positrons can also be used to constrain DM annihilation or decay in the galactic halo. The radio signal due to synchrotron radiation of electrons and positrons on the galactic magnetic field, gamma rays from bremsstrahlung processes on the galactic gas densities and from Inverse Compton scattering processes on the interstellar radiation field are considered. With several magnetic field configurations, propagation scenarios and improved gas density maps and interstellar radiation field, state-of-art tools allowing the computaion of synchrotron and bremssttrahlung radiation for any WIMP DM model are provided. All numerical results for DM are incorporated in the release of the Poor Particle Physicist Cookbook for DM Indirect Detection (PPPC4DMID). Finally, the possible GeV gamma-ray excess identified in the Fermi-LAT data from the Galactic Center in terms of DM annihilation, either in hadronic or leptonic channels is studied. In order to test this tantalizing interprestation, a multi-messenger approach is used: first, the computation of secondary emisison from DM with respect to previous works confirms it to be relevant for determining the DM spectrum in leptonic channels. Second, limits from antiprotons severely constrain the DM interpretation of the excess in the hadronic channel, for standard assumptions on the Galactic propagation parameters and solar modulation. However, they considerably relax if more conservative choices are adopted.

Author: Roberto Battiston
Publisher: World Scientific
ISBN: 9814487775
Category : Science
Languages : en
Pages : 269

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This book presents the progress in cosmic ray physics following the recent results obtained by balloon, satellite and underground experiments. The following topics are reviewed: Composition and propagation of cosmic rays, trapping of charged particles in the earth's magnetic field, atmospheric neutrinos, and high energy photon measurements in space.

Author: Jelena Aleksić
Publisher: Springer
ISBN: 3319231235
Category : Science
Languages : en
Pages : 213

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This thesis presents the results of indirect dark matter searches in the gamma-ray sky of the near Universe, as seen by the MAGIC Telescopes. The author has proposed and led the 160 hours long observations of the dwarf spheroidal galaxy Segue 1, which is the deepest survey of any such object by any Cherenkov telescope so far. Furthermore, she developed and completely characterized a new method, dubbed “Full Likelihood”, that optimizes the sensitivity of Cherenkov instruments for detection of gamma-ray signals of dark matter origin. Compared to the standard analysis techniques, this novel approach introduces a sensitivity improvement of a factor of two (i.e. it requires 4 times less observation time to achieve the same result). In addition, it allows a straightforward merger of results from different targets and/or detectors. By selecting the optimal observational target and combining its very deep exposure with the Full Likelihood analysis of the acquired data, the author has improved the existing MAGIC bounds to the dark matter properties by more than one order of magnitude. Furthermore, for particles more massive than a few hundred GeV, those are the strongest constraints from dwarf galaxies achieved by any gamma-ray instrument, both ground-based or space-borne alike.

Author: Tanushree Basak
Publisher: Morgan & Claypool Publishers
ISBN: 1643271326
Category : Science
Languages : en
Pages : 63

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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.

Author:
Publisher: World Scientific
ISBN: 981447651X
Category :
Languages : en
Pages : 81

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Author: Emilio Borchi
Publisher: World Scientific
ISBN: 9814482579
Category : Science
Languages : en
Pages : 795

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The exploration of the subnuclear world is carried out through increasingly complex experiments covering a wide range of energies and in a large variety of environments — from particle accelerators and underground detectors to satellites and space laboratories. For these research programs to succeed, novel techniques, new materials and new instrumentation need to be used in detectors, often on a large scale. This book reviews the advances made in all technological aspects of the experiments at various stages.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings® (ISTP® / ISI Proceedings)• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)• CC Proceedings — Engineering & Physical Sciences

Author: Enrico Morgante
Publisher: Springer
ISBN: 3319676067
Category : Science
Languages : en
Pages : 223

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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.

Author: Andrea Albert
Publisher: Morgan & Claypool Publishers
ISBN: 1681742691
Category : Science
Languages : en
Pages : 64

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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.