Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 6
Book Description
New Limits on Dark Matter Annihilation from AMS Cosmic Ray Positron Data
Author: AMS-02 Dark Matter Search Inspecting Cosmic Ray Positron Spectrum
Author: Elisa FalchiniDark Matter Indirect Detection with Charged Cosmic Rays
Author: Gaelle GiesenPublisher:
ISBN:
Category :
Languages : en
Pages : 0
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.
Science With The Cherenkov Telescope Array
Author: The Cta ConsortiumPublisher: World Scientific
ISBN: 9813270101
Category : Science
Languages : en
Pages : 365
Book Description
This book summarizes the science to be carried out by the upcoming Cherenkov Telescope Array, a major ground-based gamma-ray observatory that will be constructed over the next six to eight years. The major scientific themes, as well as core program of key science projects, have been developed by the CTA Consortium, a collaboration of scientists from many institutions worldwide.CTA will be the major facility in high-energy and very high-energy photon astronomy over the next decade and beyond. CTA will have capabilities well beyond past and present observatories. Thus, CTA's science program is expected to be rich and broad and will complement other major multiwavelength and multimessenger facilities. This book is intended to be the primary resource for the science case for CTA and it thus will be of great interest to the broader physics and astronomy communities. The electronic version (e-book) is available in open access.
Particle Cosmology and Astrophysics
Author: Dan HooperPublisher: Princeton University Press
ISBN: 0691235066
Category : Science
Languages : en
Pages : 449
Book Description
A graduate-level introduction to the interface between particle physics, astrophysics, and cosmology This book explores the exciting interface between the fields of cosmology, high-energy astrophysics, and particle physics, at a level suitable for advanced undergraduate- to graduate-level students as well as active researchers. Without assuming a strong background in particle physics or quantum field theory, the text is designed to be accessible to readers from a range of backgrounds and presents both fundamentals and modern topics in a modular style that allows for flexible use and easy reference. It offers coverage of general relativity and the Friedmann equations, early universe thermodynamics, recombination and the cosmic microwave background, Big Bang nucleosynthesis, the origin and detection of dark matter, the formation of large-scale structure, baryogenesis and leptogenesis, inflation, dark energy, cosmic rays, neutrino and gamma-ray astrophysics, supersymmetry, Grand Unified Theories, sterile neutrinos, and axions. The book also includes numerous worked examples and homework problems, many with solutions. Particle Cosmology and Astrophysics provides readers with an invaluable entrée to this cross-disciplinary area of research and discovery. Accessible to advanced undergraduate to graduate students, as well as researchers in cosmology, high-energy astrophysics, and particle physics Does not assume a strong background in particle physics or quantum field theory and contains two chapters specifically for readers with no background in particle physics Broad scope, covering many topics across particle physics, astrophysics, and particle cosmology Modular presentation for easy reference and flexible use Provides more than 200 homework problems, many with solutions Ideal for course use or self-study and reference
New Era For Cp Asymmetries: Axions And Rare Decays Of Hadrons And Leptons
Author: Ikaros I BigiPublisher: World Scientific
ISBN: 9813233095
Category : Science
Languages : en
Pages : 354
Book Description
This book is dedicated to Lev Okun, who passed away in November 2015. He was a true pioneer in probing fundamental dynamics.The book has two objectives. First is to showcase Okun's impact for decades since 1963, when he published his remarkable book Weak Interaction of Elementary Particles. Second is to present the current progress of our scientific community in the studies of our Universe. New directions and possible future developments are discussed, often using the past as a guide. The authors mostly focus on CP asymmetries in the transitions of hadrons and leptons, but they also discuss their rare decays, and talk about axions and supersymmetry, and possible connections with dark matter, extra dimensions, baryogenesis and multiverse.This book is suitable for readers who know quantum mechanics and quantum field theories in general.
Matter, Anti-matter And Dark Matter, Proceedings Of The Second International Workshop
Author: Roberto BattistonPublisher: World Scientific
ISBN: 9814487775
Category : Science
Languages : en
Pages : 269
Book Description
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.
Cosmic Ray Physics
Author: Veronica BindiPublisher: CRC Press
ISBN: 1000850838
Category : Science
Languages : en
Pages : 325
Book Description
Key features: Complete introductory overview of cosmic ray physics Covers the origins, acceleration, transport mechanisms and detection of these particles Mathematical and technical detail is kept separate from the main text
Origin of Cosmic Rays
Author: Vitaliĭ Lazarevich GinzburgPublisher:
ISBN:
Category :
Languages : en
Pages : 62
Book Description
Refined Predictions for Cosmic Rays and Indirect Dark Matter Searches
Author: Yoann GenoliniPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
A hundred years ago, pioneering observations of air ionization revealed that the Earth is showered with particles coming from the Galaxy and beyond. Because of their high energies, these particles coined cosmic-rays are still a crucial tool in the field of particle physics, complementary to man-made accelerators. From an astrophysical point of view, the origin of cosmic-rays and the mechanisms which accelerate them are still very poorly known. The present paradigm involves sporadic production associated with the expanding shock waves from dying stars (SNRs).Recent experiments (notably PAMELA and, more recently, AMS-02) are ushering us into a new era of measurements of cosmic-ray fluxes with greatly reduced statistical uncertainties. In this dissertation, we propose and investigate new theoretical refinements of our predictions to fully benefit from these advances.After a general introduction on cosmic-ray physics, we first focus on the so-called primary species which are directly produced by SNRs. In this context of precision measurements, the discreteness of the sources in space and time, together with a substantial ignorance of their precise epochs and locations (with the possible exception of the most recent and close ones) may lead to significant uncertainties in the predictions of the fluxes at the Earth. So far, the conventional approach just relied on average trends. Here, we elaborate a statistical theory in order to compute the probability for the actual flux to depart from its ensemble average. Using the generalized version of the central limit theorem, we demonstrate that the probability distribution function of the flux is intimately related to the source distribution and follows a stable law with a heavier tail than the Gaussian distribution. Our theoretical framework can not only be extended to other cosmic-ray observables, such as the lepton flux, but also can be enriched to include a more comprehensive description of the correlations between the sources. Moreover the method which we have developed may be applied to a variety of problems in physics/astrophysics involving heavy tail distributions.Secondly, we concentrate on secondary CRs, like the boron nuclei, which are thought to be produced only by the collisions of cosmic-rays on the interstellar medium. More precisely, the ratio of the boron to carbon fluxes is a traditional tool used to understand and gauge the propagation of cosmic-rays in the Galaxy. Hence a very precise measurement of this ratio should imply stringent constraints on the propagation scenario. However we show that its theoretical derivation strongly depends on where these secondary species are produced as well as on the chosen set of nuclear cross-sections. Hence we assess at the 20% level the theoretical uncertainties on the so far derived propagation parameters. As new data from AMS-02 were freshly released, we present the starting points of a comprehensive new analysis for which we use the semi-analytical code USINE.Finally these high precision measurements offer new opportunities for a number of astroparticle problems, such as indirect dark matter searches which is the main thrust of the third part of the thesis. Antimatter cosmic rays are thought to be secondary species and their relatively low fluxes make them a channel of choice to look for rare processes such as dark matter annihilation. Nonetheless, the predictions of the expected backgrounds rely on a precise modeling of cosmic-ray propagation and interactions in the Galaxy. We treat them under commonly used simplified assumptions and discuss two studies where we re-evaluate the anti-proton and the positron fluxes in the light of the new AMS-02 data. Then we discuss the implications for dark matter and astrophysical explanations.