Author: A. GabuttiPublisher:
ISBN:
Category :
Languages : en
Pages : 35
Book Description
Light Neutralinos as Dark Matter in the Constrained Minimal Supersymmetric Standard Model
Author: A. GabuttiLight neutralinos as dark matter in the unconstrained minimal supersymmetric standard model
Author: Supersymmetric Dark Matter Candidates in Light of Constraints from Collider and Astroparticle Observables
Author: Jonathan Da SilvaPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
The Standard Model of particle physics has been strengthened by the recent discovery of the long-awaited Higgs boson. The standard cosmological model has met the challenge of the high precision observations in comology and astroparticle physics. However these two standard models face both several theoretical issues, such as the naturalness problem in the Higgs sector of the Standard Model, as well as observational issues, in particular the fact that an unknown kind of matter called Dark Matter accounts for the majority of the matter content in our Universe. Attempts to solve such problems have led to the development of New Physics models during the last decades. Supersymmetry is one such model which addresses the fine-tuning problem in the Higgs sector and provides viable Dark Matter candidates. Current high energy and high precision experiments give many new opportunities to probe the supersymmetric models. It is in this context that this thesis is written. Considering the Minimal Supersymmetric Standard Model (MSSM), the simplest supersymmetric extension of the Standard Model of particle physics, and its conventional Dark Matter candidate, the neutralino, it is shown that collider constraints could provide informations on the very early Universe at the inflation area. It is also demonstrated that the Indirect Detection of Dark Matter, despite several drawbacks, can be a powerful technique to probe supersymmetric Dark Matter models. Beyond the MSSM it is shown that unique characteristics of the Dark Matter candidate in the NMSSM could be probed at colliders. The study of a supersymmetric model with an extended gauge symmetry, the UMSSM, is also developed. The features of another Dark Matter candidate of this model, the Right-Handed sneutrino, are analysed. More general constraints such as those coming from low energy observables are finally considered in this model.
Dark Matter Constraints on Supersymmetric Extensions of the Standard Model
Author: Andreas le Fevre Birkedal-HansenPublisher:
ISBN:
Category :
Languages : en
Pages : 286
Book Description
Supersymmetric Dark Matter Above the W Mass
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722792091
Category :
Languages : en
Pages : 62
Book Description
The cosmological consequences are studied for the minimal supersymmetric extension of the standard model in the case that the neutralino is heavier than W. The cross section was calculated for annihilation of heavy neutralinos into final states containing gauge and Higgs bosons (XX yields WW, ZZ, HH, HW, HZ), where X is the lightest, nth neutralino and the results are compared with the results with those previously obtained for annihilation into fermions to find the relic cosmological abundance for the most general neutralino. The new channels are particularly important for the Higgsino-like and mixed-state neutralinos, but are sub-dominant (to the fermion-antifermion annihilation channels) in the case that the neutralino is mostly a gaugino. The effect of the top quark mass is also considered. Using these cross sections and the cosmological constraint omega(sub X)h squared is less than or approximately 1, the entire range of cosmologically acceptable supersymmetric parameter space is mapped and a very general bound on the neutralino mass is discovered. For a top quark mass of less than 180 GeV, neutralinos heavier than 3200 GeV are cosmologically inconsistent, and if the top quark mass is less than 120 GeV, the bound is lowered to 2600 GeV. Neutralino states that are mostly gaugino are constrained to be lighter than 550 GeV. It is found that a heavy neutralino that contributes omega(sub X) is approximately 1 arises for a very wide range of model parameters and makes, therefore, a very natural and attractive dark matter candidate. Griest, Kim and Kamionkowski, Marc and Turner, Michael S. Unspecified Center...
Light Neutralino Dark Matter in the NMSSM.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 28
Book Description
Neutralino dark matter is generally assumed to be relatively heavy, with a mass near the electroweak scale. This does not necessarily need to be the case, however. In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and other supersymmetric models with an extended Higgs sector, a very light CP-odd Higgs boson can naturally arise making it possible for a very light neutralino to annihilate efficiently enough to avoid being overproduced in the early Universe. In this article, we explore the characteristics of a supersymmetric model needed to include a very light neutralino, 100 MeV
Non-standard Models of Dark Matter and Their Experimental Signatures
Author: Marat FreytsisPublisher:
ISBN:
Category :
Languages : en
Pages : 200
Book Description
The weakly interacting massive particle (WIMP) paradigm gives an elegant mechanism for the generation of dark matter densities with the appropriate properties to be consistent with current observations. While in its minimal implementation, the only opportunity to test the reality of the scenario is by directly detecting the WIMP itself, cosmic ray anomalies observed several years ago imply the possibility of an extended dark matter sector in which secondary annihilations or decays can occur before interacting with the standard model. This opens up the possibility of detecting other parts of dark sector in a much wider set of experiments than those typically considered in connection to dark matter. In this dissertation I study several alternative models, capable of yielding signals across a broad range of experimental approaches. I study the prospects for detecting a light boson X with mass mX ≤ 100 MeV at a low energy electron-proton collider. Focus is on the case where X dominantly decays to e+e- as motivated by recent "dark force" models. In order to evade direct and indirect constraints, X must have small couplings to the standard model ([alpha]X ≤ 10-8) and a sufficiently large mass (mX ≥ 10 MeV). By comparing the signal and background cross sections for the $e-p e+e- final state, I conclude that dark force detection requires an integrated luminosity of around 1 ab-1. This proposal is currently being implements by the DarkLight collaboration at the Thomas Jefferson National Accelerator Facility. I also investigate the bounds on axion-like states from flavor-changing neutral current b → s decays, assuming the axion couples to the standard model through mixing with the Higgs sector. Such GeV-scale axions have received renewed attention in connection with observed cosmic ray excesses. I find that existing B → K l+l- data impose stringent bounds on the axion decay constant in the multi-TeV range, relevant for constraining the "axion portal" model of dark matter. Such bounds also constrain light Higgs scenarios in the next-to-minimal supersymmetric standard model. These bounds can be improved by dedicated searches in B-factory data and at LHCb. While looking at direct dark matter detection experiments themselves, it is often assumed that the first evidence for dark matter will come from experiments probing spin-independent interactions, with much higher sensitivities due to coherence effects. I explore models that would be invisible in such experiments, but detectable via spin-dependent interactions. The existence of much larger (or even only) spin-dependent tree-level interactions is not sufficient, due to potential spin-independent subdominant or loop-induced interactions, and I find that in this way most models with detectable spin-dependent interactions would also generate detectable spin-independent interactions. Models in which a light pseudoscalar acts as the mediator seem to uniquely evade this conclusion. In presenting a particular viable dark matter model generating such an interaction, a tens of MeV--GeV-scale axion is found to be an attractive candidate independently of considerations presented earlier.
Supersymmetric Dark Matter in the NMSSM and E6SSM
Author: Sophie UnderwoodPublisher:
ISBN:
Category : Dark matter (Astronomy)
Languages : en
Pages : 144
Book Description
Supersymmetric extensions of the standard model may resolve the outstanding dark matter problem by producing viable dark matter candidates, including a stable weakly interacting particle called a neutralino. The next-to-minimal supersymmetric standard model (NMSSM) is first explored with a scan of the parameter space for neutralino-hadron scattering using an updated value for the strange quark sigma commutator. This is followed by an extensive exploration of the parameter space of the E6-inspired supersymmetric standard model (E6SSM). It is demonstrated that this model still provides neutralino dark matter candidates that may be detected in the near-future by upcoming experiments, despite tightening experimental constraints.
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.
Yet Another Introduction to Dark Matter
Author: Martin BauerPublisher: Springer
ISBN: 3030162346
Category : Science
Languages : en
Pages : 180
Book Description
Dark matter is a frequently discussed topic in contemporary particle physics. Written strictly in the language of particle physics and quantum field theory, these course-based lecture notes focus on a set of standard calculations that students need in order to understand weakly interacting dark matter candidates. After introducing some general features of these dark matter agents and their main competitors, the Higgs portal scalar and supersymmetric neutralinos are introduced as our default models. In turn, this serves as a basis for exploring four experimental aspects: the dark matter relic density extracted from the cosmic microwave background; indirect detection including the Fermi galactic center excess; direct detection; and collider searches. Alternative approaches, like an effective theory of dark matter and simplified models, naturally follow from the discussions of these four experimental directions.