SEARCHING FOR HIGGS BOSONS AND NEW PHYSICS AT HADRON COLLIDERS. PDF Download

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Languages : en
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The objectives of research activities in particle theory are predicting the production cross section and decay branching fractions of Higgs bosons and new particles at hadron colliders, developing techniques and computer software to discover these particles and to measure their properties, and searching for new phenomena and new interactions at the Fermilab Tevatron and the CERN Large Hadron Collider. The results of our project could lead to the discovery of Higgs bosons, new particles, and signatures for new physics, or we will be able to set meaningful limits on important parameters in particle physics. We investigated the the prospects for the discovery at the CERN Large Hadron Collider of Higgs bosons and supersymmetric particles. Promising results are found for the CP-odd pseudoscalar ($A^0$) and the heavier CP-even scalar ($H^0$) Higgs bosons with masses up to 800 GeV. Furthermore, we study properties of the lightest neutralino ($\chi^0$) and calculate its cosmological relic density in a supersymmetric $U(1)'$ model as well as the muon anomalous magnetic moment $a_\mu = (g_\mu - 2)/2$ in a supersymmetric $U(1)'$ model. We found that there are regions of the parameter space that can explain the experimental deviation of $a_\mu$ from the Standard Model calculation and yield an acceptable cold dark matter relic density without conflict with collider experimental constraints. % Recently, we presented a complete next-to-leading order (NLO) calculation for the total cross section of inclusive Higgs pair production via bottom-quark fusion ($b\bar{b} \to hh$) at the CERN Large Hadron Collider (LHC) in the Standard Model and the minimal supersymmetric model. We plan to predict the Higgs pair production rate and to study the trilinear coupling among the Higgs bosons. % In addition, we have made significant contributions in B physics, single top production, charged Higgs search at the Fermilab as well as in grid computing for both D0 and ATLAS.

Author: Luis Roberto Flores Castillo
Publisher: Morgan & Claypool Publishers
ISBN: 1681741423
Category : Science
Languages : en
Pages : 104

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This book provides a general description of the search for and discovery of the Higgs boson (particle) at CERN’s Large Hadron Collider. The goal is to provide a relatively brief overview of the issues, instruments and techniques relevant for this search; written by a physicist who was directly involved. The Higgs boson mat be the one particle that was studied the most before its discovery and the story from postulation in 1964 to detection in 2012 is a fascinating one. The story is told here while detailing the fundamentals of particle physics.

Author: Roger Wolf
Publisher: Springer
ISBN: 3319185128
Category : Science
Languages : en
Pages : 192

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This book provides a comprehensive overview of the field of Higgs boson physics. It offers the first in-depth review of the complete results in connection with the discovery of the Higgs boson at CERN’s Large Hadron Collider and based on the full dataset for the years 2011 to 2012. The fundamental concepts and principles of Higgs physics are introduced and the important searches prior to the advent of the Large Hadron Collider are briefly summarized. Lastly, the discovery and first mensuration of the observed particle in the course of the CMS experiment are discussed in detail and compared to the results obtained in the ATLAS experiment.

Author: Scientific American Editors
Publisher: Scientific American
ISBN: 1466824131
Category : Science
Languages : en
Pages : 467

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The Higgs Boson: Searching for the God Particle by the Editors of Scientific American Updated 2017 Edition! For the fifth anniversary of one of the biggest discoveries in physics, we’ve updated this eBook to include our continuing analysis of the discovery, of the questions it answers and those it raises. As the old adage goes, where there’s smoke, there’s fire. Where there is effect, there must be cause. The planet Neptune was found in 1846 because the mathematics of Newton's laws, when applied to the orbit of Uranus, said some massive body had to be there. Astronomers eventually found it, using the best telescopes available to peer into the sky. This same logic is applied to the search for the Higgs boson. One consequence of the prevailing theory of physics, called the Standard Model, is that there has to be some field that gives particles their particular masses. With that there has to be a corresponding particle, made by creating waves in the field, and this is the Higgs boson, the so-called God particle. This eBook chronicles the search – and demonstrates the power of a good theory. Based on the Standard Model, physicists believed something had to be there, but it wasn't until the Large Hadron Collider was built that anyone could see evidence of the Higgs – and finally in July 2012, they did. A Higgs-like particle was found near the energies scientists expected to find it. Now, armed with better evidence and better questions, the scientific process continues. This eBook gathers the best reporting and analysis from Scientific American to explain that process – the theories, the search, the ongoing questions. In essence, everything you need to know to separate Higgs from hype.

Author: Aleandro Nisati
Publisher: World Scientific
ISBN: 981442546X
Category : Science
Languages : en
Pages : 470

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The recent observation of the Higgs boson has been hailed as the scientific discovery of the century and led to the 2013 Nobel Prize in physics. This book describes the detailed science behind the decades-long search for this elusive particle at the Large Electron Positron Collider at CERN and at the Tevatron at Fermilab and its subsequent discovery and characterization at the Large Hadron Collider at CERN. Written by physicists who played leading roles in this epic search and discovery, this book is an authoritative and pedagogical exposition of the portrait of the Higgs boson that has emerged from a large number of experimental measurements. As the first of its kind, this book should be of interest to graduate students and researchers in particle physics.

Author: Amir D. Aczel
Publisher: Crown
ISBN: 0307591824
Category : Science
Languages : en
Pages : 290

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The Large Hadron Collider (LHC) is the biggest, and by far the most powerful, machine ever built. A project of CERN, the European Organization for Nuclear Research, its audacious purpose is to re-create, in a 16.5-mile-long circular tunnel under the French-Swiss countryside, the immensely hot and dense conditions that existed some 13.7 billion years ago within the first trillionth of a second after the fiery birth of our universe. In Present at the Creation, Amir D. Aczel takes us inside the control rooms, as an international team of researchers begins to discover whether a multibillion-euro investment will fulfill its promise: to find empirical confirmation of theories in physics and cosmology. Through the eyes and words of the men and women who conceived and built CERN and the LHC, Aczel enriches all of us with a firm grounding in the scientific concepts necessary to appreciate fully the stunning July 4, 2012 discovery of the Higgs Boson. Newly updated in the wake of the discovery, Present at the Creation tells the story of perhaps the greatest experiment in the history of science.

Author: Jon Butterworth
Publisher: The Experiment
ISBN: 1615192468
Category : Science
Languages : en
Pages : 308

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An accessible account of the work leading up to the monumental discovery of the Higgs boson, from one of the physicists who was there. Particle physics as we know it depends on the Higgs boson: It’s the missing link between the birth of our universe—as a sea of tiny, massless particles—and the tangible world we live in today. But for more than 50 years, scientists wondered: Does it exist? Physicist Jon Butterworth was at the frontlines of the hunt for the Higgs at CERN’s Large Hadron Collider—perhaps the most ambitious experiment in history. In Most Wanted Particle, he gives us the first inside account of that uncertain time, when an entire field hinged on a single particle, and life at the cutting edge of science meant media scrutiny, late-night pub debates, dispiriting false starts in the face of intense pressure, and countless hours at the collider itself. As Butterworth explains, our first glimpse of the elusive Higgs brings us a giant step closer to understanding the universe—and points the way to an entirely new kind of physics. Praise for Most Wanted Particle “Butterworth is an insider’s insider. His narrative seethes with insights on the project’s science, technology and “tribes,” as well as his personal (and often amusing) journey as a frontier physicist.” —Nature “A vivid account of what the process of discovery was really like for an insider.” —Peter Higgs, winner of the Nobel Prize in Physics “If you want to know why the discovery of the Higgs boson matters, read this book!” —Brian Cox, author of Why Does E=mc2?

Author: Daniel Denegri
Publisher: World Scientific
ISBN: 9813236108
Category : Science
Languages : en
Pages : 620

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An introduction to the world of quarks and leptons, and of their interactions governed by fundamental symmetries of nature, as well as an introduction to the connection that exists between worlds of the infinitesimally small and the infinitely large.The book begins with a simple presentation of the theoretical framework, the so-called Standard Model, which evolved gradually since the 1960s. The key experiments establishing it as the theory of elementary particle physics, but also its missing pieces and conceptual weaknesses are introduced. The book proceeds with the extraordinary story of the Large Hadron Collider at CERN — the largest purely scientific project ever realized. Conception, design and construction by worldwide collaborations of the detectors of size and complexity without precedent in scientific history are discussed. The book then offers the reader a state-of-the art (2020) appreciation of the depth and breadth of the physics exploration performed by the LHC experiments: the study of new forms of matter, the understanding of symmetry-breaking phenomena at the fundamental level, the exciting searches for new physics such as dark matter, additional space dimensions, new symmetries, and more. The adventure of the LHC culminated in the discovery of the Higgs boson in 2012 (Nobel Prize in Physics in 2013). The last chapter of this book describes the plans for the LHC during the next 15 years of exploitation and improvement, and the possible evolution of the field and future collider projects under consideration.The authors are researchers from CERN, CEA and CNRS (France), and deeply engaged in the LHC program: D Denegri in the CMS experiment, C Guyot, A Hoecker and L Roos in the ATLAS experiment. Some of them are involved since the inception of the project. They give a lively and accessible inside view of this amazing scientific and human adventure.

Author: Paul Halpern
Publisher: John Wiley & Sons
ISBN: 0470286202
Category : Science
Languages : en
Pages : 274

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Book Description
An accessible look at the hottest topic in physics and the experiments that will transform our understanding of the universe The biggest news in science today is the Large Hadron Collider, the world's largest and most powerful particle-smasher, and the anticipation of finally discovering the Higgs boson particle. But what is the Higgs boson and why is it often referred to as the God Particle? Why are the Higgs and the LHC so important? Getting a handle on the science behind the LHC can be difficult for anyone without an advanced degree in particle physics, but you don't need to go back to school to learn about it. In Collider, award-winning physicist Paul Halpern provides you with the tools you need to understand what the LHC is and what it hopes to discover. Comprehensive, accessible guide to the theory, history, and science behind experimental high-energy physics Explains why particle physics could well be on the verge of some of its greatest breakthroughs, changing what we think we know about quarks, string theory, dark matter, dark energy, and the fundamentals of modern physics Tells you why the theoretical Higgs boson is often referred to as the God particle and how its discovery could change our understanding of the universe Clearly explains why fears that the LHC could create a miniature black hole that could swallow up the Earth amount to a tempest in a very tiny teapot "Best of 2009 Sci-Tech Books (Physics)"-Library Journal "Halpern makes the search for mysterious particles pertinent and exciting by explaining clearly what we don't know about the universe, and offering a hopeful outlook for future research."-Publishers Weekly Includes a new author preface, "The Fate of the Large Hadron Collider and the Future of High-Energy Physics" The world will not come to an end any time soon, but we may learn a lot more about it in the blink of an eye. Read Collider and find out what, when, and how.

Author: My Phuong Thi Le
Publisher: Stanford University
ISBN:
Category :
Languages : en
Pages : 277

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Book Description
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 ($m_{\tilde {g}}$, $m_{\tilde {W}}$, $m_{\tilde {B}}$).