Download or read book Dileptons and Jets at the LHC written by Christopher Edward Justus and published by . This book was released on 2012 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis presents the results from two searches using dileptons and jetsbased on 4.98 fb-1 of data taken by the CMS experiment at the Large HadronCollider during the 2011 run. The first is part of a larger, complete search forsupersymmetry using the signal of one isolated lepton, jets and missing transverseenergy. Although the search concentrates on a single lepton topology, this thesisoutlines the procedure to predict the contribution from dilepton events which, through various processes, feed down into the single lepton control sample. Thesecond is a search for massive, exotic, colored fermions decaying to two jets and alepton by looking for a peak in the lepton plus two jet invariant mass spectrum. Adata-driven method has been developed in order to make a background prediction. The observations are consistent with the standard model background prediction. The results are presented as limits on the cross section of such exotic fermions asa function of mass.
Download or read book Dilepton Tagged Jets in Heavy Ion Collisions at the LHC written by and published by . This book was released on 2010 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dilepton tagged QQ Jet Events at the LHC written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We propose a new method for identifying and isolating Q{bar Q} + jet events through semileptonic decays of the Q{bar Q} pair. Employing these decay dileptons to tag the jet in a specific kinematic region provides a clean signature of jets associated with heavy-quark production. The measurement, in both pp and heavy-ion collisions, is essential for addressing heavy-quark fragmentation in vacuum and in a dense medium. We present next-to-leading order calculations of Q{bar Q} production (leading order in Q{bar Q} jet production) in (square root)s = 14 TeV pp collisions at the LHC and discuss the feasibility of the measurement in heavy-ion collisions at (square root)s{sub NN} = 5.5 TeV.
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 for New Physics in Events with Same sign Dileptons and Jets in Pp Collisions at sqrt s written by and published by . This book was released on 2014 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search for new physics is performed based on events with jets and a pair of isolated, same-sign leptons. The results are obtained using a sample of proton-proton collision data collected by the CMS experiment at a centre-of-mass energy of 8 TeV at the LHC, corresponding to an integrated luminosity of 19.5 inverse femtobarns. In order to be sensitive to a wide variety of possible signals beyond the standard model, multiple search regions defined by the missing transverse energy, the hadronic energy, the number of jets and b-quark jets, and the transverse momenta of the leptons in the events are considered. No excess above the standard model background expectation is observed and constraints are set on a number of models for new physics, as well as on the same-sign top-quark pair and quadruple-top-quark production cross sections. As a result, information on event selection efficiencies is also provided, so that the results can be used to confront an even broader class of new physics models.
Download or read book Dilepton Tagged Q Qbar Jet Events at the LHC written by and published by . This book was released on 2008 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We propose a new method for identifying and isolating Q{bar Q}+jet events through semileptonic decays of the Q{bar Q} pair. Employing these decay dileptons to tag the jet in a specific kinematic region provides a clean signature of jets associated with heavy quark production. The measurement, in both pp and heavy-ion collisions, is essential for addressing heavy quark fragmentation in the vacuum and in a dense medium. We present next-to-leading order calculations of Q{bar Q} production (leading order in Q{bar Q}+jet production) in (square root)s = 14 TeV pp collisions at the LHC and discuss the feasibility of the measurement in heavy-ion collisions at (square root)s{sub NN} = 5.5 TeV.
Download or read book Search for New Physics with Same sign Isolated Dilepton Events with Jets and Missing Transverse Energy at the LHC written by and published by . This book was released on 2011 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of searches for new physics in events with two same-sign isolated leptons, hadronic jets, and missing transverse energy in the final state are presented. The searches use an integrated luminosity of 35 inverse picobarns of pp collision data at a centre-of-mass energy of 7 TeV collected by the CMS experiment at the LHC. The observed numbers of events agree with the standard model predictions, and no evidence for new physics is found. To facilitate the interpretation of our data in a broader range of new physics scenarios, information on our event selection, detector response, and efficiencies is provided.
Download or read book Jet Quenching in Relativistic Heavy Ion Collisions at the LHC written by Aaron Angerami and published by Springer Science & Business Media. This book was released on 2013-12-02 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the first measurements of jets in relativistic heavy ion collisions as reported by the ATLAS Collaboration. These include the first direct observation of jet quenching through the observation of a centrality-dependent dijet asymmetry. Also, a series of jet suppression measurements are presented, which provide quantitative constraints on theoretical models of jet quenching. These results follow a detailed introduction to heavy ion physics with emphasis on the phenomenon of jet quenching and a comprehensive description of the ATLAS detector and its capabilities with regard to performing these measurements.
Download or read book Advances in Jet Substructure at the LHC written by Roman Kogler and published by Springer Nature. This book was released on 2021-05-10 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the reader to the field of jet substructure, starting from the basic considerations for capturing decays of boosted particles in individual jets, to explaining state-of-the-art techniques. Jet substructure methods have become ubiquitous in data analyses at the LHC, with diverse applications stemming from the abundance of jets in proton-proton collisions, the presence of pileup and multiple interactions, and the need to reconstruct and identify decays of highly-Lorentz boosted particles. The last decade has seen a vast increase in our knowledge of all aspects of the field, with a proliferation of new jet substructure algorithms, calculations and measurements which are presented in this book. Recent developments and algorithms are described and put into the larger experimental context. Their usefulness and application are shown in many demonstrative examples and the phenomenological and experimental effects influencing their performance are discussed. A comprehensive overview is given of measurements and searches for new phenomena performed by the ATLAS and CMS Collaborations. This book shows the impressive versatility of jet substructure methods at the LHC.
Download or read book High Jet Multiplicity Physics at the LHC written by Mireia Crispín Ortuzar and published by Springer. This book was released on 2016-08-25 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes research in two different areas of state-of-the-art hadron collider physics, both of which are of central importance in the field of particle physics. The first part of the book focuses on the search for supersymmetric particles called gluinos. The book subsequently presents a set of precision measurements of “multi-jet” collision events, which involve large numbers of newly created particles, and are among the dominant processes at the Large Hadron Collider (LHC). Now that a Higgs boson has been discovered at the LHC, the existence (or non-existence) of supersymmetric particles is of the utmost interest and significance, both theoretically and experimentally. In addition, multi-jet collision events are an important background process for a wide range of analyses, including searches for supersymmetry.
Download or read book A Search for New Physics in Events with Oppositely Charged Dileptons Jets and Missing Transverse Energy in Proton proton Collisions at 7 TeV Center of Mass Energy written by Derek Michael Barge and published by . This book was released on 2014 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy of 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 inverse femto-barns. The search strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not explicitly considered.
Download or read book Probing New Physics with Jets at the LHC written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Large Hadron Collider at CERN has the potential to make a major discovery as early as 2008 from simple measurements of events with two high energy jets. This talk will present the jet trigger and analysis plans of the CMS collaboration, which were produced at the LHC Physics Center at Fermilab. Plans to search the two jet channel for generic signals of new particles and forces will be discussed. I will present the anticipated sensitivity of the CMS experiment to a variety of models of new physics, including quark compositeness, technicolor, superstrings, extra dimensions and grand unification.
Download or read book Search for New Physics in a Final State with Same Sign Dileptons Jets and Missing Transverse Energy at 7 TeV Center of Mass Energy written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for new physics in a final state with two same sign leptons, missing transverse energy, and significant hadronic activity at a center of mass energy $\sqrt{s}$ = 7 TeV. The data were collected with the CMS detector at the CERN LHC and correspond to an integrated luminosity of 0.98 $\mathrm{fb}^{-1}$. Data--driven methods are developed to estimate the dominant Standard Model backgrounds. No evidence for new physics is observed. The dominant background to the analysis comes from failures of lepton identification in Standard Model $t\bar{t}$ events. The $t\bar{t}$ production cross section in the dilepton final state is measured using 3.1 $\mathrm{fb}^{-1}$ of data. The cross section is measured to be 194 $\pm$ 72 (stat) $\pm$ 24 (syst) $\pm$ 21 (lumi) pb. An algorithm is developed that uses tracking information to improve the reconstruction of missing transverse energy. The reconstruction of missing transverse energy is commissioned using the first collisio ns recorded at 0.9, 2.36 and 7 TeV data. Events with abnormally large values of missing transverse energy are identified as arising from anomalous signals in the calorimeters. Tools are developed to identify and remove these anomalous signals.
Download or read book Search for New Physics in a Final State with Same sign Dileptons Jets and Missing Transverse Energy at 7 TeV Center of Mass Energy written by Frank Golf and published by . This book was released on 2012 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on a search for new physics in a final state with two same sign leptons, missing transverse energy, and significant hadronic activity at a center of mass energy sqrt(s) = 7 TeV. The data were collected with the CMS detector at the CERN LHC and correspond to an integrated luminosity of 0.98 inverse femtobarns. Data-driven methods are developed to estimate the dominant Standard Model backgrounds. No evidence for new physics is observed. The dominant background to the analysis comes from failures of lepton identification in Standard Model ttbar events. The ttbar production cross section in the dilepton final state is measured using 3.1 inverse picobarns of data. The cross section is measured to be 194 ± 72 (stat) ± 24 (syst) ± 21 (lumi) pb. An algorithm is developed that uses tracking information to improve the reconstruction of missing transverse energy. The reconstruction of missing transverse energy is commissioned using the first collisions recorded at 0.9, 2.36 and 7 TeV data. Events with abnormally large values of missing transverse energy are identified as arising from anomalous signals in the calorimeters. Tools are developed to identify and remove these anomalous signals.
Download or read book Inclusive b Jet Production in Proton Proton Collisions written by Patrick L.S. Connor and published by Springer Nature. This book was released on 2019-11-29 with total page 325 pages. Available in PDF, EPUB and Kindle. Book excerpt: ^ 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.
Download or read book Probing the Quark gluon Plasma at the LHC with Z0 tagged Jets in CMS written by and published by . This book was released on 2007 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important tool in quark-gluon plasma studies at RHIC has been the measurement of dijets investigated via leading hadron correlations. With much higher rates for hard processes at the Large Hadron Collider, studies of Z°-tagged jets become possible. A clear experimental signature is provided by the measurement of muon pairs from the Z° decays, for which CMS is an ideally suited detector. Instead of measuring back-to-back correlations of two strongly interacting particles, one side is replaced by an electromagnetic probe which propagates through the plasma undisturbed and provides a measurement of the energy of the initial hard scattering. We propose to use lepton-pair tagged jets to study medium-induced partonic energy loss and to measure in-medium parton fragmentation functions. The lepton pairs from semileptonic decays of heavy meson pairs (B{bar B} and D{bar D}) are a background source for the tagged dilepton-jet signal. We present the calculated signal rates (using PYTHIA) and background rates (using HVQMNR). We also discuss strategies for maximizing the signal-to-background ratio.
Download or read book Jet Reconstruction in W Jets Events at the LHC written by Ulrike Schnoor and published by . This book was released on 2010 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
