Searching For New Physics At Small And Large Scales


Searching For New Physics At Small And Large Scales
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Searching For New Physics At Small And Large Scales


Searching For New Physics At Small And Large Scales
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Author : Martin Schmaltz
language : en
Publisher: World Scientific
Release Date : 2013-08-28

Searching For New Physics At Small And Large Scales written by Martin Schmaltz and has been published by World Scientific this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-08-28 with Science categories.


This volume is a compilation of the lectures at TASI 2012, held in Boulder, Colorado, June 2012. The program comprises two parallel lecture series on particle physics and on cosmology. The particle physics lectures covers LHC related experimental techniques, phenomenology, as well as basics in physics beyond the standard model. The cosmology series give a general introduction to modern cosmology with special attention to the topics of dark matter, the microwave background and alternatives to the standard model of cosmology. The lectures are accessible to graduate students at the initial stages of their research careers. Contents:Dark Energy Models (R R Caldwell)Cosmological Perturbations (J Lesgourges)Implications of the Higgs Boson and the LHC for the MSSM (A Pierce)Astrophysical Probes of Dark Matter (S Profumo)Modified Gravity (F Schmidt)TASI 2012 Lectures on Inflation (L Senatore)Jet Substructure (J Shelton)Introduction to QCD (P Skands)Super-Tricks for Superspace (D Bertolini, J Thaler and Z Thomas)TASI 2012 Participants (The Students) Readership: Graduate students and researchers in high energy physics, astroparticle physics and cosmology. Keywords:High Energy Physics;Cosmology;Dark Matter;Physics Beyond Standard Model



Indirect Searches For New Physics


Indirect Searches For New Physics
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Author : Alexey A. Petrov
language : en
Publisher: CRC Press
Release Date : 2021-05-03

Indirect Searches For New Physics written by Alexey A. Petrov and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-05-03 with Science categories.


This is the first book to discuss the search for new physics in charged leptons, neutrons, and quarks in one coherent volume. The area of indirect searches for new physics is highly topical; though no new physics particles have yet been observed directly at the Large Hadron Collider at CERN, the methods described in this book will provide researchers with the necessary tools to keep searching for new physics. It describes the lines of research that attempt to identify quantum effects of new physics particles in low-energy experiments, in addition to detailing the mathematical basis and theoretical and phenomenological methods involved in the searches, whilst making a clear distinction between model-dependent and model-independent methods employed to make predictions. This book will be a valuable guide for graduate students and early-career researchers in particle and high energy physics who wish to learn about the techniques used in modern predictions of new physics effects at low energies, whilst also serving as a reference for researchers at other levels. Key features: • Takes an accessible, pedagogical approach suitable for graduate students and those seeking an overview of this new and fast-growing field • Illustrates common theoretical trends seen in different subfields of particle physics • Valuable both for researchers in the phenomenology of elementary particles and for experimentalists



Aspects Of Wimp Dark Matter Searches At Colliders And Other Probes


Aspects Of Wimp Dark Matter Searches At Colliders And Other Probes
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Author : Enrico Morgante
language : en
Publisher: Springer
Release Date : 2017-10-05

Aspects Of Wimp Dark Matter Searches At Colliders And Other Probes written by Enrico Morgante and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-10-05 with Science categories.


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.



A Search For Exotic Higgs Decays


A Search For Exotic Higgs Decays
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Author : Jackson Burzynski
language : en
Publisher: Springer Nature
Release Date : 2023-05-23

A Search For Exotic Higgs Decays written by Jackson Burzynski and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-05-23 with Science categories.


The absence of new physics at the TeV scale observed thus far at the Large Hadron Collider (LHC) motivates an increasing focus on searches for weakly-coupled new particles and exotic signatures. In particular, particles with macroscopic mean proper lifetimes, known as long-lived particles (LLPs), are of significant interest due to their ability to elude the majority of searches which rely on the assumption that Beyond Standard Model particles decay close to the primary interaction point. Many models which aim to solve various issues with the Standard Model (SM) introduce new particles with lifetimes that are either unconstrained, or even shown to prefer the macroscopic regime. These theories often point to the Higgs boson as a possible portal to new physics, with exotic Higgs decays being the primary phenomenological consequence and means of discovery. It is well motivated both from theory and experimental constraints to consider the scenario in which the particles produced in these exotic decays have macroscopic proper lifetimes and give rise to unique detector signatures. This work describes a search for exotic decays of the Higgs boson to two long-lived, neutral, spin-0 particles which subsequently decay to pairs of b quarks, giving the striking signature of displaced hadronic jets in the ATLAS inner detector. Several other ATLAS searches have probed this decay topology previously, excluding branching ratios of the Higgs boson to LLPs of more than 10% for proper lifetimes greater than 100mm. These searches relied on dedicated triggers designed to select events with LLPs decaying in the ATLAS calorimeter or muon spectrometer. The lack of an equivalent trigger for LLP decays in the ATLAS inner detector has been a limiting factor in probing LLP lifetimes less than 100mm. To circumvent the difficulty of triggering on LLP decays, the search presented in this thesis exploits the ZH associated production mode, relying on leptonic trigger signatures to select interesting events. This is the first search for Higgs boson decays into LLPs to exploit this analysis methodology and additionally makes use of several novel methods for both background rejection and background estimation. No excess over Standard Model predictions is observed, and upper limits are set on the branching ratio of the Higgs boson to LLPs . Depending on the mass of the LLP, branching ratios greater than 10% are excluded for lifetimes as small as 4mm and as large as 100mm, probing an important gap in the ATLAS exotic Higgs decay programme. In comparison to the previous searches for Higgs decays to LLPs, these are among the most stringent limits placed on this scenario, and for LLPs with masses below 40 GeV these results represent the strongest existing constraints on the branching ratio of the Higgs boson to LLPs in this lifetime regime.



Indirect Searches For New Physics


Indirect Searches For New Physics
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Author : Alexey A. Petrov
language : en
Publisher: CRC Press
Release Date : 2021-05-04

Indirect Searches For New Physics written by Alexey A. Petrov and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-05-04 with Science categories.


This is the first book to discuss the search for new physics in charged leptons, neutrons, and quarks in one coherent volume. The area of indirect searches for new physics is highly topical; though no new physics particles have yet been observed directly at the Large Hadron Collider at CERN, the methods described in this book will provide researchers with the necessary tools to keep searching for new physics. It describes the lines of research that attempt to identify quantum effects of new physics particles in low-energy experiments, in addition to detailing the mathematical basis and theoretical and phenomenological methods involved in the searches, whilst making a clear distinction between model-dependent and model-independent methods employed to make predictions. This book will be a valuable guide for graduate students and early-career researchers in particle and high energy physics who wish to learn about the techniques used in modern predictions of new physics effects at low energies, whilst also serving as a reference for researchers at other levels. Key features: • Takes an accessible, pedagogical approach suitable for graduate students and those seeking an overview of this new and fast-growing field • Illustrates common theoretical trends seen in different subfields of particle physics • Valuable both for researchers in the phenomenology of elementary particles and for experimentalists



Beyond The Standard Model Cocktail


Beyond The Standard Model Cocktail
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Author : Yann Gouttenoire
language : en
Publisher: Springer Nature
Release Date : 2023-01-01

Beyond The Standard Model Cocktail written by Yann Gouttenoire and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-01-01 with Science categories.


This book provides a remarkable and complete survey of important questions at the interface between theoretical particle physics and cosmology. After discussing the theoretical and experimental physics revolution that led to the rise of the Standard Model in the past century, the author reviews all the major open puzzles, among them the hierarchy problem, the small value of the cosmological constant, the matter-antimatter asymmetry, and the dark matter enigma, including the state-of-the-art regarding proposed solutions. Also addressed are the rapidly expanding fields of thermal dark matter, cosmological first-order phase transitions and gravitational-wave signatures. In addition, the book presents the original and interdisciplinary PhD research work of the author relating to Weakly-Interacting-Massive-Particles around the TeV scale, which are among the most studied dark matter candidates. Motivated by the absence of experimental evidence for such particles, this thesis explores the possibility that dark matter is much heavier than what is conventionally assumed.



Sterile Neutrino Dark Matter


Sterile Neutrino Dark Matter
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Author : Alexander Merle
language : en
Publisher: Morgan & Claypool Publishers
Release Date : 2017-05-10

Sterile Neutrino Dark Matter written by Alexander Merle and has been published by Morgan & Claypool Publishers this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-05-10 with Science categories.


This book is a new look at one of the hottest topics in contemporary science, Dark Matter. It is the pioneering text dedicated to sterile neutrinos as candidate particles for Dark Matter, challenging some of the standard assumptions which may be true for some Dark Matter candidates but not for all. So, this can be seen either as an introduction to a specialized topic or an out-of-the-box introduction to the field of Dark Matter in general. No matter if you are a theoretical particle physicist, an observational astronomer, or a ground based experimentalist, no matter if you are a grad student or an active researcher, you can benefit from this text, for a simple reason: a non-standard candidate for Dark Matter can teach you a lot about what we truly know about our standard picture of how the Universe works.



Searches For New Physics At Colliders


Searches For New Physics At Colliders
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Author : My Phuong Thi Le
language : en
Publisher: Stanford University
Release Date : 2011

Searches For New Physics At Colliders written by My Phuong Thi Le and has been published by Stanford University this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.


The turning-on of the Large Hadron Collider is the momentous milestone in our quest for new physics beyond the Standard Model. Soon, we will be presented with the task of detecting, identifying, and studying the possibly large parameter space of the underlying model. In this thesis, we will look at some possible extensions to the SM, their signatures at colliders, and possible search strategies to explore the new physics in a model-independent way. In chapter 2, we study the extended neutral gauge sector of the Littlest Higgs model at the 500 GeV e+e- collider using the fermion pair production and Higgs associate production channel. We find that these channels can provide an accurate determination of the fundamental parameters and thus allows the verification of the little Higgs mechanism designed to cancel the Higgs mass quadratic divergence. In chapter 3, we study the ATLAS supersymmetry searches proposed for the 14 TeV pp collider using the $\sim$ 70k models of the phenomenological Minimal Supersymmetric Model (pMSSM) moldel set, that have survived many theoretical and experimental constraints. Since pMSSM does not make any simplifying assumptions about its SUSY-breaking mechanism at high scale, this encompasses a broad class of Supersymmetric models. We find that even though these searches were optimized mostly for mSUGRA signals, they are relatively robust in observing the more general pMSSM models. For the case of models in which squarks and gluinos have mass below 1 TeV, essentially all of these models ($> 99\%$) were observable in at least one of these searches, with 1 $fb^{-1}$ of integrated luminosity allowing for an uncertainty of 50\% in the SM background. We found that 0-lepton searches are the most powerful searches, while searches with 1-2 leptons do not have coverage as good as has been shown for mSUGRA. We then study possible reasons why a model could not be observed. These difficult models mostly include those with long-lived charginos which lead to small Missing Tranverse Energy (MET) and models with squeezed spectra which lead to soft jets that fail the jet cuts. In chapter 4, we study similar searches that have been carried out by ATLAS at the 7 TeV LHC. We found that systematic uncertainty again plays an important role in determining the coverage of the searches. This is especially true for searches with a large SM background, such as $n$-jet 0 lepton searches. We study the implication of a null result from the 7 TeV LHC. We find that the degree of fine-tuning in the pMSSM depends on the prior in which we scan our 19-dimensional space, but overall it is not as large as in mSUGRA. We find that a null result at the 7 TeV with $10 fb^{-1}$ and 20\% systematic errors would imply a need for a higher energy e+e- machine than the 500 GeV ILC to study Supersymmetry. Continuing on along the line of Supersymmetry, in chapter 5 we explore the possibility of adding one more generation to the MSSM (4GMSSM). We find that the CP-odd A boson can be very light due to the contribution of the heavy 4th generation fermion loops while all other Higgs particles (including the CP-even {\it h}) are all quite heavy. The parameter $tan(\beta)$ is strongly constrained to be between 0.5 and 2 due to perturbativity requirements on Yukawa couplings. We study the electroweak constraints as well as collider signatures on the possibility of a light A of mass $\sim$115 GeV. As for an LHC discovery, we find that this light A can be seen in the standard 2-photon Higgs search channel with cross-section more than an order of magnitude greater than that of the SM Higgs. In the last two chapters, we study possible search strategies to explore the new physics in a model-independent way. In chapter 6, we attempt to show how one could be largely agnostic about the underlying model in exploring the complete kinematically-allowed parameter space of pair-produced color octet particles (with mass $m_{\tilde{g}}$) that each directly decay into two jets plus a neutral stable particle (with mass $m_{\tilde{B}}$) that would escape the detectors and appear as MET. The kinematics of this process can be completely described by two parameters $m_{\tilde {g}}$ and $m_{\tilde {B}}$ , and in particular their splitting determines the softness or hardness of jets from the decay products. In order to cover the whole parameter space, one would need separate searches for different regions. We show that optimizing the final cuts for every ($m_{\tilde {g}}$, $m_{\tilde {B}}$) point, and combining all searches, can extend the coverage significantly. Since this is just based on the kinematics of the decay, this result can be easily interpreted for any model with this decay topology. In chapter 7, we carry this model-independent approach further in jets plus missing energy searches, by proposing that one should bin the measured data (or simulated SM background) differentially in MET and $H_T$ (scalar sum of invisible energy) for each search, and use them to set limits on any model of interest. We demonstrate this technique by carrying out a search similar to that studied in chapter 6, with one added decay step for the color octet particle, mainly it decays to 2 jets and another particle (with mass $m_{\tilde {W}}$) and it in turn decays to the neutral stable particle and 2 jets. We study different kinematic regions and set bounds in this 3-dimensional parameter space ($m_{\tilde {g}}$, $m_{\tilde {W}}$, $m_{\tilde {B}}$).



Inclusive B Jet Production In Proton Proton Collisions


Inclusive B Jet Production In Proton Proton Collisions
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Author : Patrick L.S. Connor
language : en
Publisher: Springer Nature
Release Date : 2019-11-29

Inclusive B Jet Production In Proton Proton Collisions written by Patrick L.S. Connor and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-11-29 with Science categories.


^ 74 GeV and |y| 2.4; the b jets must contain a B hadron. The measurement has significant statistics up to p T ∼ O(TeV). Advanced methods of unfolding are performed to extract the signal. It is found that fixed-order calculations with underlying event describe the measurement well.



The Search For Supersymmetry In Hadronic Final States Using Boosted Object Reconstruction


The Search For Supersymmetry In Hadronic Final States Using Boosted Object Reconstruction
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Author : Giordon Stark
language : en
Publisher: Springer Nature
Release Date : 2020-03-13

The Search For Supersymmetry In Hadronic Final States Using Boosted Object Reconstruction written by Giordon Stark and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-03-13 with Science categories.


This thesis represents one of the most comprehensive and in-depth studies of the use of Lorentz-boosted hadronic final state systems in the search for signals of Supersymmetry conducted to date at the Large Hadron Collider. A thorough assessment is performed of the observables that provide enhanced sensitivity to new physics signals otherwise hidden under an enormous background of top quark pairs produced by Standard Model processes. This is complemented by an ingenious analysis optimization procedure that allowed for extending the reach of this analysis by hundreds of GeV in mass of these hypothetical new particles. Lastly, the combination of both deep, thoughtful physics analysis with the development of high-speed electronics for identifying and selecting these same objects is not only unique, but also revolutionary. The Global Feature Extraction system that the author played a critical role in bringing to fruition represents the first dedicated hardware device for selecting these Lorentz-boosted hadronic systems in real-time using state-of-the-art processing chips and embedded systems.