Indirect Searches for New Physics

Indirect Searches for New Physics PDF Author: Alexey A. Petrov
Publisher: CRC Press
ISBN: 1351176005
Category : Science
Languages : en
Pages : 218

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Book Description
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

Indirect Searches for New Physics

Indirect Searches for New Physics PDF Author: Alexey A. Petrov
Publisher: CRC Press
ISBN: 1351176005
Category : Science
Languages : en
Pages : 218

Get Book Here

Book Description
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

Searches for New Physics at Colliders

Searches for New Physics at Colliders PDF 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 ($m_{\tilde {g}}$, $m_{\tilde {W}}$, $m_{\tilde {B}}$).

Cbt Workshop

Cbt Workshop PDF Author: F. Caruso
Publisher: Atlantica Séguier Frontières
ISBN: 9782863321874
Category : Heavy particles (Nuclear physics)
Languages : en
Pages : 558

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Book Description


Search For New Elementary Particles, The: Status And Prospect - Proceedings Of The Trieste Workshop

Search For New Elementary Particles, The: Status And Prospect - Proceedings Of The Trieste Workshop PDF Author: Martin Lewis Perl
Publisher: World Scientific
ISBN: 9814553662
Category :
Languages : en
Pages : 315

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Book Description
It has been more than a decade since new elementary particles were discovered. To recognize the findings of scientists in this still fairly new but exciting and promising area of research, the Trieste Workshop was organised in May 1992 to discuss the status and explore the prospects for the discovery of new elementary particles using the full variety of search methods which are, or will be available to the physicist. All papers in this collection of proceedings are reviews written by experts in their own area of speciality. Many review papers based on experimental findings are also included. To present a clearer and more coherent overview, a theoretical overview talk as well as a summary talk have been included to serve as a link between the various areas that were discussed in the papers. This collection of papers is perhaps the first authoritative source ever published on the search for new elementary particles.

Search for New Physics in tt ̅ Final States with Additional Heavy-Flavor Jets with the ATLAS Detector

Search for New Physics in tt ̅ Final States with Additional Heavy-Flavor Jets with the ATLAS Detector PDF Author: Javier Montejo Berlingen
Publisher: Springer
ISBN: 3319410512
Category : Science
Languages : en
Pages : 288

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Book Description
This doctoral thesis focuses on the search for new phenomena in top-antitop quark (tt) final states with additional b-quark jets at the LHC. It uses the full Run 1 dataset collected by the ATLAS experiment in proton-proton collisions at √s=8 TeV. The final state of interest consists of an isolated lepton, a neutrino and at least six jets with at least four b-tagged jets, a challenging experimental signature owing to the large background from tt+heavy-flavor production. This final state is characteristic of ttH production, with the Higgs boson decaying into bb, a process that allows direct probing of the top-Higgs Yukawa coupling. This signature is also present in many extensions of the Standard Model that have been proposed as solutions to the hierarchy problem, such as supersymmetry or composite Higgs models, which predict the pair production of bosonic or fermionic top quark partners, or the anomalous production of four-top-quark events. All these physics processes have been searched for using an ambitious search strategy that has been developed on the basis of a combination of state-of-art theoretical predictions and a sophisticated statistical analysis to constrain in-situ the large background uncertainties. As a result, the most restrictive bounds to date on the above physics processes have been obtained.

CP Violation

CP Violation PDF Author: I. I. Bigi
Publisher: Cambridge University Press
ISBN: 052184794X
Category : Science
Languages : en
Pages : 506

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Book Description
Why did the matter in our Universe not annihilate itself with antimatter immediately after its creation? The discovery of CP violation may answer this fundamental question and this book presents information and tools necessary to its understanding.

B Physics And Cp Violation: Proceedings Of The 2nd International Conference

B Physics And Cp Violation: Proceedings Of The 2nd International Conference PDF Author: Thomas E Browder
Publisher: World Scientific
ISBN: 9814602760
Category :
Languages : en
Pages : 528

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Book Description
CP violation is one of the most subtle effects in the Standard Model of particle physics and may be the first clue to the physics that lies beyond. Charge conjugation, C, and parity, P, are symmetries of particle interactions. C corresponds to the operation of replacing a particle by its antiparticle, while P is the operation of mirror reflection. Before 1956, it was believed that these were also symmetries of the interactions of elementary particles. In 1956, C S Wu found evidence for P violation in the weak interaction. Theorists proposed that the combination of CP would be a symmetry of the weak interaction. In 1964, Christenson, Cronin, Fitch and Turlay found the first evidence for the violation of CP symmetry in the decays of kaons.Although Kobayashi and Maskawa then showed how the Standard Model can accommodate the observed CP violation, Wolfenstein pointed out that it is also possible that there is a new interaction in addition to the usual four, called the superweak interaction, which is responsible for the asymmetry. To test this idea, the observation of a different type of asymmetry, called direct CP violation, is required; in the kaon sector, very precise measurements of the ratio of kaon decay rates are necessary. In B decay modes where a second order weak process whimisically named “penguin” interferes with another suppressed, first order “tree” amplitude, it may also be possible to observe these direct CP-violating effects.B physics and CP violation is now one of the major growth areas in high energy physics. Nearly every major high energy physics laboratory now has a project underway to observe the large CP asymmetries expected in the B sector and to test the consistency of the Standard Model. The unitarity of the Kobayashi-Maskawa mixing matrix in the Standard Model implies the existence of three phases, called alpha, beta and gamma, which can be determined by the measurements of CP asymmetries in B decays. About 200 participants gathered in Hawaii in March 1997 to discuss the progress in the field, and this important book constitutes the proceedings of that conference.

CP Violation: From Quarks to Leptons

CP Violation: From Quarks to Leptons PDF Author: M. Giorgi
Publisher: IOS Press
ISBN: 1614990190
Category : Science
Languages : en
Pages : 613

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Book Description
For a long time after the discovery in 1964, by Christenson, Cronin, Fitch and Turlay, that the long-lived neutral kaon decays both into three and into two pions, which has since been taken as proof of CP violation, successive new and more precise experiments confirmed the original evidence and provided results compatible with a phenomenological description confining the CP violation to the mixing between neutral kaons and antikaons. However the Standard Model, with three generations of quarks, linking as it does CP violation to the presence of a single non trivial phase in the Cabibbo-Kobayashi-Maskawa quark mixing matrix, implies that if CP violation exists at all, then it is a general property of weak interactions, appearing in transitions were amplitudes involving all three quark families interfere with each other, producing effects with a magnitude related to that of the CKM coefficients. This fact has stimulated an impressive amount of theoretical work leading in many cases to precise predictions. This publication reviews the field, from both the theoretical and experimental point of view, while planning for the forthcoming experimentation at LHC and considering possible new facilities for kaon, B meson and neutrino physics. Abstracted in Inspec

High Energy Physics: Ichep 2000 - Proceedings Of The 30th International Conference (In 2 Volumes)

High Energy Physics: Ichep 2000 - Proceedings Of The 30th International Conference (In 2 Volumes) PDF Author: Chong-sa Lim
Publisher: World Scientific
ISBN: 9813201177
Category : Science
Languages : en
Pages : 1550

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Book Description
This book presents topics of major interest to the high energy physics community, as well as recent research results.

Quark Confinement and the Hadron Spectrum VII

Quark Confinement and the Hadron Spectrum VII PDF Author: Jose Emilio F. T. Ribeiro
Publisher: AIP Conference Proceedings (Nu
ISBN:
Category : Science
Languages : en
Pages : 580

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Book Description
This volume features papers presented at the 7th Conference on Quark Confinement and the Hadron Spectrum. It covers the up-to-date research done in the physics of quarks and their role as ultimate constituents of matter. It will be of interest to all theoreticians and experimentalists working in these areas.