Science

In Search of Dark Matter

Author: Ken Freeman

Publisher: Springer Science & Business Media

ISBN:

Category: Science

Page: 158

View: 630

Written for the educated non-scientist and scientist alike, it spans a variety of scientific disciplines, from observational astronomy to particle physics. Concepts that the reader will encounter along the way are at the cutting edge of scientific research. However the themes are explained in such a way that no prior understanding of science beyond a high school education is necessary.
Science

Matter, Dark Matter, and Anti-Matter

Author: Alain Mazure

Publisher: Springer Science & Business Media

ISBN:

Category: Science

Page: 172

View: 350

For over ten years, the dark side of the universe has been headline news. Detailed studies of the rotation of spiral galaxies, and 'mirages' created by clusters of galaxies bending the light from very remote objects, have convinced astronomers of the presence of large quantities of dark (unseen) matter in the cosmos. The most striking fact is that they seem to compromise about 95% of the matter/energy content of the universe. As for ordinary matter, although we are immersed in a sea of dark particles, including primordial neutrinos and photons from fossil cosmological radiation, both we and our environment are made of ordinary, 'baryonic' matter. Authors Mazure and Le Brun present the inventory of matter, baryonic and exotic, and investigating the nature and fate of matter's twin, anti-matter. They show how technological progress has been a result of basic research, in tandem with the evolution of new ideas, and how the combined effect of these advances might help lift the cosmic veil.
Science

Sources and Detection of Dark Matter and Dark Energy in the Universe

Author: David Cline

Publisher: Springer Science & Business Media

ISBN:

Category: Science

Page: 136

View: 388

These proceedings provide the latest results on dark matter and dark energy research. The UCLA Department of Physics and Astronomy hosted its tenth Dark Matter and Dark Energy conference in Marina del Rey and brought together all the leaders in the field. The symposium provided a scientific forum for the latest discussions in the field. Topics covered at the symposium: •Status of measurements of the equation of state of dark energy and new experiments •The search for missing energy events at the LHC and implications for dark matter search •Theoretical calculations on all forms of dark matter (SUSY, axions, sterile neutrinos, etc.) •Status of the indirect search for dark matter •Status of the direct search for dark matter in detectors around the world •The low-mass wimp search region •The next generation of very large dark matter detectors •New underground laboratories for dark matter search
Science

Search for Dark Matter with the ATLAS Detector

Author: Johanna Gramling

Publisher: Springer

ISBN:

Category: Science

Page: 282

View: 914

This book discusses searches for Dark Matter at the CERN’s LHC, the world’s most powerful accelerator. It introduces the relevant theoretical framework and includes an in-depth discussion of the Effective Field Theory approach to Dark Matter production and its validity, as well as an overview of the formalism of Simplified Dark Matter models. Despite overwhelming astrophysical evidence for Dark Matter and numerous experimental efforts to detect it, the nature of Dark Matter still remains a mystery and has become one of the hottest research topics in fundamental physics. Two searches for Dark Matter are presented, performed on data collected with the ATLAS experiment. They analyze missing-energy final states with a jet or with top quarks. The analyses are explained in detail, and the outcomes and their interpretations are discussed, also in view of the precedent analysis of theoretical approaches. Given its depth of coverage, the book represents an excellent reference guide for all physicists interested in understanding the theoretical and experimental considerations relevant to Dark Matter searches at the LHC.
Science

Search for Dark Matter Produced in Association with a Higgs Boson Decaying to Two Bottom Quarks at ATLAS

Author: Yangyang Cheng

Publisher: Springer

ISBN:

Category: Science

Page: 176

View: 555

This thesis reports on the search for dark matter in data taken with the ATLAS detector at CERN’s Large Hadron Collider (LHC). The identification of dark matter and the determination of its properties are among the highest priorities in elementary particle physics and cosmology. The most likely candidate, a weakly interacting massive particle, could be produced in the high energy proton-proton collisions at the LHC. The analysis presented here is unique in looking for dark matter produced together with a Higgs boson that decays into its dominant decay mode, a pair of b quarks. If dark matter were seen in this mode, we would learn directly about the production mechanism because of the presence of the Higgs boson. This thesis develops the search technique and presents the most stringent production limit to date.
Science

Dark Matter in the Universe

Author: John N. Bahcall

Publisher: World Scientific

ISBN:

Category: Science

Page: 233

View: 623

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 review volume is the extended editon of the lectures given in the 4th Jerusalem Winter School of Theoretical Physics, with new materials added in. It devoted to the discussion of the so-called "missing matter" problem in the universe - dark matter and dark energy. The goal of this volume is to make current research work on unseen matter accessible to students of faculties without prior experience in this area. Due to the pedagogical nature of the notes and the intense discussions between students and the lecturers, the written lectures included in this volume often contain techniques and explanations not found in more formal journal publications.

Search for the Production of Dark Matter in Association with Top-Quark Pairs in the Single-Lepton Final State in Proton-Proton Collisions at $\sqrt{s}$

Author:

Publisher:

ISBN:

Category:

Page:

View: 875

A search is presented for particle dark matter produced in association with a pair of top quarks in pp collisions at a centre-of-mass energy of s√=8 TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 19.7 fb-1. This search requires the presence of one lepton, multiple jets, and large missing transverse energy. No excess of events is found above the SM expectation, and upper limits are derived on the production cross section. Interpreting the findings in the context of a scalar contact interaction between fermionic dark matter particles and top quarks, lower limits on the interaction scale are set. These limits are also interpreted in terms of the dark matter-nucleon scattering cross sections for the spin-independent scalar operator and they complement direct searches for dark matter particles in the low mass region.

Advancing the Search for Dark Matter

Author:

Publisher:

ISBN:

Category:

Page: 248

View: 600

An overwhelming proportion of the universe (83% by mass) is composed of particles we know next to nothing about. Detecting these dark matter particles directly, through hypothesized weak-force-mediated recoils with nuclear targets here on earth, could shed light on what these particles are, how they relate to the standard model, and how the standard model ts within a more fundamental understanding. This thesis describes two such experimental eorts: CDMS II (2007-2009) and SuperCDMS Soudan (ongoing). The general abilities and sensitivities of both experiments are laid out, placing a special emphasis on the detector technology, and how this technology has evolved from the rst to the second experiment. Some topics on which I spent signicant eorts are described here only in overview (in particular the details of the CDMS II analysis, which has been laid out many times before), and some topics which are not described elsewhere are given a somewhat deeper treatment. In particular, this thesis is hopefully a good reference for those interested in the annual modulation limits placed on the low-energy portion of the CDMS II exposure, the design of the detectors for SuperCDMS Soudan, and an overview of the extremely informative data these detectors produce. It is an exciting time. The technology I've had the honor to work on the past few years provides a wealth of information about each event, more so than any other direct detection experiment, and we are still learning how to optimally use all this information. Initial tests from the surface and now underground suggest this technology has the background rejection abilities necessary for a planned 200kg experiment or even ton-scale experiment, putting us on the threshold of probing parameter space orders of magnitude from where the eld currently stands.
Science

Search for Dark Matter with ATLAS

Author: Ruth Pöttgen

Publisher: Springer

ISBN:

Category: Science

Page: 322

View: 632

This thesis describes in detail a search for weakly interacting massive particles as possible dark matter candidates, making use of so-called mono-jet events. It includes a detailed description of the run-1 system, important operational challenges, and the upgrade for run-2. The nature of dark matter, which accounts for roughly 25% of the energy-matter content of the universe, is one of the biggest open questions in fundamental science. The analysis is based on the full set of proton-proton collisions collected by the ATLAS experiment at the Large Hadron Collider at √s = 8 TeV. Special attention is given to the experimental challenges and analysis techniques, as well as the overall scientific context beyond particle physics. The results complement those of non-collider experiments and yield some of the strongest exclusion bounds on parameters of dark matter models by the end of the Large Hadron Collider run-1. Details of the upgrade of the ATLAS Central Trigger for run-2 are also included.