Download or read book Next to leading Order QCD Predictions for W 2 Jet and Z 2 Jet Production at the CERN LHC written by John Campbell and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Next to leading Order 2 jet Production at the LHC written by and published by . This book was released on 2014 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present next-to-leading-order QCD predictions for cross sections and for a comprehensive set of distributions in ??+2-jet production at the Large Hadron Collider. We consider the contributions from loop amplitudes for two photons and four gluons, but we neglect top quarks. We use BlackHat together with SHERPA to carry out the computation. We use a Frixione cone isolation for the photons. We study standard sets of cuts on the jets and the photons and also sets of cuts appropriate for studying backgrounds to Higgs-boson production via vector-boson fusion.
Download or read book Perspectives on Lhc Physics written by G. L. Kane and published by World Scientific. This book was released on 2008 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Large Hadron Collider (LHC), located at CERN, Geneva, Switzerland, is the world's largest and highest energy and highest intensity particle accelerator. Here is a timely book with several perspectives on the hoped-for discoveries from the LHC.This book provides an overview on the techniques that will be crucial for finding new physics at the LHC, as well as perspectives on the importance and implications of the discoveries. Among the accomplished contributors to this book are leaders and visionaries in the field of particle physics beyond the Standard Model, including two Nobel Laureates (Steven Weinberg and Frank Wilczek), and presumably some future Nobel Laureates, plus top younger theorists and experimenters. With its blend of popular and technical contents, the book will have wide appeal, not only to physical scientists but also to those in related fields.
Download or read book Jet Physics at the LHC written by Klaus Rabbertz and published by Springer. This book was released on 2016-10-11 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the latest experimental results on jet physics from proton-proton collisons at the LHC. Jets allow to determine the strong coupling constant over a wide range of energies up the highest ones possible so far, and to constrain the gluon parton distribution of the proton, both of which are important uncertainties on theory predictions in general and for the Higgs boson in particular.A novel approach in this book is to categorize the examined quantities according to the types of absolute, ratio, or shape measurements and to explain in detail the advantages and differences. Including numerous illustrations and tables the physics message and impact of each observable is clearly elaborated.
Download or read book Search Strategies for New Physics at the LHC written by Daniele Spier Moreira Alves and published by Stanford University. This book was released on 2011 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The LHC is in the frontline of experimental searches for New Physics beyond the Standard Model of Particle Physics. Its power is accompanied by no smaller challenges in analyzing and interpreting its results. In this thesis I explore ways to parameterize new physics phenomena, design search strategies that are sensitive to them, and interpret experimental results in general new physics contexts. In particular, I discuss interpretations of the first ATLAS analysis for supersymmetry with 70/nb of integrated luminosity. I also carry a careful investigation of comprehensive search strategies for new physics with jets and missing energy signatures, and estimate the sensitivity bounds of the 7 TeV LHC to new colored particles decaying to jets and and a neutral particle that escapes detection. Finally, I discuss the implications of the recent LHC excesses hinting to a Higgs boson with mass in the range 142-147 GeV. If confirmed, this range for the Higgs mass will be an important evidence for Split Supersymmetry. I work out the phenomenological predictions of this scenario that will be tested in the very near future by a variety of experiments, including direct and indirect dark matter detection, EDM experiments searching for CP violation and the 7 TeV run of the LHC.
Download or read book NLO QCD Corrections to Vector Boson Production in Association with Multiple Heavy and Light Jets written by Felix Richard Anger and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Precise theory predictions for scattering processes are an important input for the physics program at the Large Hadron Collider at CERN, Geneva. Notably the complex collider signatures of an electroweak vector boson and many jets that originate in either light partons (light jets) or bottom quarks (b jets) are relevant for both measurements of Standard Model processes as well as searches for new physics. In this thesis, we present new next-to-leading order QCD predictions for two related high-multiplicity processes at the LHC $\sqrt{s} = 13$ TeV. We show predictions for $Wb\bar{b}$ production in association with two and three light jets that we computed for the first time. In order to obtain the required one-loop amplitudes, we implement the numerical unitarity approach for massive particles in a new version of the BlackHat library. To this end, we devise and apply a new algorithm for the evaluation of D-dimensional unitarity cuts. It builds on a consistent embedding of external fermions states in dimensional regularization and reduces the computational complexity of our calculations. Furthermore, we present next-to-leading order QCD predictions for $V+n$-jet production in association with up to $n = 5$ light jets for $V = W^\pm$ and with up to $n = 4$ light jets for $V = Z$, which we extend to the higher center-of-mass energy of the Large Hadron Collider Run-II. For these processes we compare results obtained with fixed-order scales such as $\hat{H}_T^'/2$ with the MiNLO reweighting procedure
Download or read book The Black Book of Quantum Chromodynamics written by John Campbell and published by Oxford University Press. This book was released on 2018 with total page 760 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title provides an in-depth introduction to the particle physics of current and future experiments at particle accelerators. The text provides the reader with an overview of practically all aspects of the strong interaction necessary to understand and appreciate modern particle phenomenology at the energy frontier.
Download or read book Next to leading Order QCD Predictions for Top quark Pair Production with Up to Two Jets Merged with a Parton Shower written by and published by . This book was released on 2015 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present differential cross sections for the production of top-quark pairs in conjunction with up to two jets, computed at next-to-leading order in perturbative QCD and consistently merged with a parton shower in the Sherpa+OpenLoops framework. Top quark decays including spin correlation effects are taken into account at leading order accuracy. The calculation yields a unified description of top-pair plus multi-jet production, and detailed results are presented for various key observables at the Large Hadron Collider. A large improvement with respect to the multi-jet merging approach at leading order is found for the total transverse energy spectrum, which plays a prominent role in searches for physics beyond the Standard Model.
Download or read book Next to Leading Order Predictions for W 3 Jet Distributions at Hadron Colliders written by and published by . This book was released on 2009 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present next-to-leading order QCD predictions for a variety of distributions in W + 3-jet production at both the Tevatron and the Large Hadron Collider. We include all subprocesses and incorporate the decay of the W boson into leptons. Our results are in excellent agreement with existing Tevatron data and provide the first quantitatively precise next-to-leading order predictions for the LHC. We include all terms in an expansion in the number of colors, confirming that the specific leading-color approximation used in our previous study is accurate to within three percent. The dependence of the cross section on renormalization and factorization scales is reduced significantly with respect to a leading-order calculation. We study different dynamical scale choices, and find that the total transverse energy is significantly better than choices used in previous phenomenological studies. We compute the one-loop matrix elements using on-shell methods, as numerically implemented in the BlackHat code. The remaining parts of the calculation, including generation of the real-emission contributions and integration over phase space, are handled by the SHERPA package.
Download or read book Next to leading Order QCD Predictions for Top quark Pair Production with Up to Three Jets written by Stefan Höche and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: We present theoretical predictions for the production of top-quark pairs with up to three jets at the next-to leading order in perturbative QCD. The relevant calculations are performed with Sherpa and OpenLoops. To address the issue of scale choices and related uncertainties in the presence of multiple scales, we compare results obtained with the standard scale HT/2 at fixed order and the MiNLO procedure. Analyzing various cross sections and distributions for tt ̄+0,1,2,3 jets at the 13 TeV LHC we find a remarkable overall agreement between fixed-order and MiNLO results. The differences are typically below the respective factor-two scale variations, suggesting that for all considered jet multiplicities missing higher-order effects should not exceed the ten percent level
Download or read book Next to Leading Order QCD Predictions for Z Gamma 3 Jet Distributions at the Tevatron written by and published by . This book was released on 2010 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using BlackHat in conjunction with SHERPA, we have computed next-to-leading order QCD predictions for a variety of distributions in Z, [gamma]{sup {asterisk}}+ 1, 2, 3-jet production at the Tevatron, where the Z boson or off-shell photon decays into an electron-positron pair. We find good agreement between the NLO results for jet {sub pT} distributions and measurements by CDF and D0. We also present jetproduction ratios, or probabilities of finding one additional jet. As a function of vector-boson {sub pT}, the ratios have distinctive features which we describe in terms of a simple model capturing leading logarithms and phase-space and parton-distribution-function suppression.
Download or read book Measurement of the Inclusive Electron Cross Section from Heavy Flavour Decays and Search for Compressed Supersymmetric Scenarios with the ATLAS Experiment written by Moritz Backes and published by Springer. This book was released on 2014-06-11 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of this thesis presents the measurement of the inclusive cross-section for electron production from heavy-flavour decays in the electron transverse momentum range 7 GeV
Download or read book Precise Predictions for W 4 Jet Production at the Large Hadron Collider written by and published by . This book was released on 2010 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the first next-to-leading order QCD results for W + 4-jet production at hadron colliders. Total cross sections, as well as distributions in the jet transverse momenta and in the total transverse energy HT, are provided for the initial LHC energy of (square root)s = 7 TeV. We use a leading-color approximation, known to be accurate to 3% for W production with fewer jets. The virtual matrix elements and the most complicated real-emission matrix elements are handled by the BlackHat library, based on on-shell methods. The remaining parts of the calculation, including the integration over phase space, are performed by the SHERPA package.
Download or read book Next to Leading Order Gamma Gamme Plus 2 Jet Production at the LHC written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present next-to-leading-order QCD predictions for cross sections and for a comprehensive set of distributions in [gamma][gamma]+2-jet production at the Large Hadron Collider. We consider the contributions from loop amplitudes for two photons and four gluons, but we neglect top quarks. We use BlackHat together with SHERPA to carry out the computation. We use a Frixione cone isolation for the photons. We study standard sets of cuts on the jets and the photons and also sets of cuts appropriate for studying backgrounds to Higgs-boson production via vector-boson fusion.
Download or read book Looking Inside Jets written by Simone Marzani and published by Springer. This book was released on 2019-05-11 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: This concise primer reviews the latest developments in the field of jets. Jets are collinear sprays of hadrons produced in very high-energy collisions, e.g. at the LHC or at a future hadron collider. They are essential to and ubiquitous in experimental analyses, making their study crucial. At present LHC energies and beyond, massive particles around the electroweak scale are frequently produced with transverse momenta that are much larger than their mass, i.e., boosted. The decay products of such boosted massive objects tend to occupy only a relatively small and confined area of the detector and are observed as a single jet. Jets hence arise from many different sources and it is important to be able to distinguish the rare events with boosted resonances from the large backgrounds originating from Quantum Chromodynamics (QCD). This requires familiarity with the internal properties of jets, such as their different radiation patterns, a field broadly known as jet substructure. This set of notes begins by providing a phenomenological motivation, explaining why the study of jets and their substructure is of particular importance for the current and future program of the LHC, followed by a brief but insightful introduction to QCD and to hadron-collider phenomenology. The next section introduces jets as complex objects constructed from a sequential recombination algorithm. In this context some experimental aspects are also reviewed. Since jet substructure calculations are multi-scale problems that call for all-order treatments (resummations), the bases of such calculations are discussed for simple jet quantities. With these QCD and jet physics ingredients in hand, readers can then dig into jet substructure itself. Accordingly, these notes first highlight the main concepts behind substructure techniques and introduce a list of the main jet substructure tools that have been used over the past decade. Analytic calculations are then provided for several families of tools, the goal being to identify their key characteristics. In closing, the book provides an overview of LHC searches and measurements where jet substructure techniques are used, reviews the main take-home messages, and outlines future perspectives.
Download or read book Precise Predictions for W 3 Jet Production at Hadron Colliders written by and published by . This book was released on 2009 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on the first next-to-leading order QCD computation of W + 3-jet production in hadronic collisions including all partonic subprocesses. We compare the results with CDF data from the Tevatron, and find excellent agreement. The renormalization and factorization scale dependence is reduced substantially compared to leading-order calculations. The required one-loop matrix elements are computed using on-shell methods, implemented in a numerical program, BlackHat. We use the SHERPA package to generate the real-emission contributions and to integrate the various contributions over phase space. We use a leading-color (large-N{sub c}) approximation for the virtual part, which we confirm in W + 1,2-jet production to be valid to within three percent. The present calculation demonstrates the utility of on-shell methods for computing next-to-leading-order corrections to processes important to physics analyses at the Large Hadron Collider.
Download or read book Next to Leading Order QCD Corrections to Vector Boson Pair Production in Association with Two Jets at the LHC written by Matthias Kerner and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
