Evidence for Spin Correlation in Tt Production

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ISBN 13 :
Total Pages : pages
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Book Synopsis Evidence for Spin Correlation in Tt Production by :

Download or read book Evidence for Spin Correlation in Tt Production written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the ratio of events with correlated t and t spins to the total number of tt events. This ratio f is evaluated using a matrix-element-based approach in 729 tt candidate events with a single lepton l (electron or muon) and at least four jets. The analyzed pp collisions data correspond to an integrated luminosity of 5.3 fb-1 and were collected with the D0 detector at the Fermilab Tevatron collider operating at a center-of-mass energy \(\sqrt{s}=1.96\) TeV. Combining this result with a recent measurement of f in dileptonic final states, we find f in agreement with the standard model. In addition, the combination provides evidence for the presence of spin correlation in tt events with a significance of more than 3 standard deviations.

Spin Correlations in tt Events from pp Collisions

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Publisher : Springer
ISBN 13 : 3319189328
Total Pages : 246 pages
Book Rating : 4.3/5 (191 download)

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Book Synopsis Spin Correlations in tt Events from pp Collisions by : Boris Lemmer

Download or read book Spin Correlations in tt Events from pp Collisions written by Boris Lemmer and published by Springer. This book was released on 2015-06-24 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis introduces readers to the Standard Model, the top quark and its properties, before explaining the concept of spin correlation measurement. The first measurement of top quark spin correlations at the LHC in the lepton+jets decay channel is presented. As the heaviest elementary particle, the top quark plays an essential role in the Standard Model of elementary particle physics. In the case of top quarks being produced in pairs at hadron colliders, the Standard Model predicts their spins to be correlated. The degree of correlation depends on both the production mechanism and properties of the top quark. Any deviation from the Standard Model prediction can be an indicator for new physics phenomena. The thesis employs an advanced top quark reconstruction algorithm including dedicated identification of the up- and down-type quarks from the W boson decay.

Evidence for Spin Correlation in $t\bar{t}$ Production

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ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (873 download)

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Book Synopsis Evidence for Spin Correlation in $t\bar{t}$ Production by :

Download or read book Evidence for Spin Correlation in $t\bar{t}$ Production written by and published by . This book was released on 2011 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a measurement of the ratio of events with correlated t and {bar t} spins to the total number of t{bar t} events. This ratio f is evaluated using a matrix-element-based approach in events with a single lepton (electron or muon) and at least four jets. We analyze p{bar p} collisions data corresponding to an integrated luminosity of 5.3 fb−1 collected with the D0 detector at the Fermilab Tevatron collider operating at a center of mass energy √s = 1.96 TeV. Combining this result with a recent measurement of f in t{bar t} → W+b W−{bar b} → l+ [nu]b l− {bar {nu}}b final states, we find f in agreement with the standard model. In addition, the combination provides evidence for the presence of spin correlation in t{bar t} events with a significance of more than three standard deviations.

Measurements of Tt{u00AF} Spin Correlations and Top Quark Polarization Using Dilepton Final States in Pp Collisions at S

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ISBN 13 :
Total Pages : pages
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Book Synopsis Measurements of Tt{u00AF} Spin Correlations and Top Quark Polarization Using Dilepton Final States in Pp Collisions at S by :

Download or read book Measurements of Tt{u00AF} Spin Correlations and Top Quark Polarization Using Dilepton Final States in Pp Collisions at S written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We presented measurements of the top quark-antiquark (tt¯) spin correlations and the top quark polarization for tt¯ pairs produced in pp collisions at √s=8 TeV. The data correspond to an integrated luminosity of 19.5 fb-1 collected with the CMS detector at the LHC. The measurements are performed using events with two oppositely charged leptons (electrons or muons) and two or more jets, where at least one of the jets is identified as originating from a bottom quark. The spin correlations and polarization are measured from the angular distributions of the two selected leptons, both inclusively and differentially, with respect to the invariant mass, rapidity, and transverse momentum of the tt¯ system. Moreover, the measurements are unfolded to the parton level and found to be in agreement with predictions of the standard model. A search for new physics in the form of anomalous top quark chromo moments is performed. Lastly, no evidence of new physics is observed, and exclusion limits on the real part of the chromo-magnetic dipole moment and the imaginary part of the chromo-electric dipole moment are evaluated.

Hadron Collider Physics 2005

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Publisher : Springer Science & Business Media
ISBN 13 : 3540328416
Total Pages : 360 pages
Book Rating : 4.5/5 (43 download)

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Book Synopsis Hadron Collider Physics 2005 by : Mario Campanelli

Download or read book Hadron Collider Physics 2005 written by Mario Campanelli and published by Springer Science & Business Media. This book was released on 2007-08-17 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of The Hadron Collider Physics Symposia (HCP) 2005, and reviews the state-of-the-art in the key physics directions of experimental hadron collider research. Topics include QCD physics, precision electroweak physics, c-, b-, and t-quark physics, physics beyond the Standard Model, and heavy ion physics. The present volume serves as a reference for everyone working in the field of accelerator-based high-energy physics.

Measurement of Tt Production Cross Section in Pp Collisions at [square Root] S

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Publisher :
ISBN 13 :
Total Pages : 418 pages
Book Rating : 4.3/5 (121 download)

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Book Synopsis Measurement of Tt Production Cross Section in Pp Collisions at [square Root] S by : Harpreet Singh

Download or read book Measurement of Tt Production Cross Section in Pp Collisions at [square Root] S written by Harpreet Singh and published by . This book was released on 1999 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Measurement of Spin Correlations in Top/Anti-Top Events from Pp Collisions at Sqrt(s)

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ISBN 13 :
Total Pages : 249 pages
Book Rating : 4.:/5 (931 download)

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Book Synopsis Measurement of Spin Correlations in Top/Anti-Top Events from Pp Collisions at Sqrt(s) by :

Download or read book Measurement of Spin Correlations in Top/Anti-Top Events from Pp Collisions at Sqrt(s) written by and published by . This book was released on 2014 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: The top quark decays before it hadronises. Before its spin state can be changed in a process of strong interaction, it is directly transferred to the top quark decay products. The top quark spin can be deduced by studying angular distributions of the decay products. The Standard Model predicts the top/anti-top quark (tt) pairs to have correlated spins. The degree is sensitive to the spin and the production mechanisms of the top quark. Measuring the spin correlation allows to test the predictions. New physics e ects can be reflected in deviations from the prediction. In this thesis the spin ...

Nuclear Science and Safety in Europe

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Publisher : Springer Science & Business Media
ISBN 13 : 140204965X
Total Pages : 289 pages
Book Rating : 4.4/5 (2 download)

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Book Synopsis Nuclear Science and Safety in Europe by : Tomas Cechák

Download or read book Nuclear Science and Safety in Europe written by Tomas Cechák and published by Springer Science & Business Media. This book was released on 2006-04-07 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results on the nature of low-, intermediate- and high-energy nuclear forces as well as on the internal structure of nucleons and atomic nuclei are presented. Prospects to find a new state of the nuclear matter at extreme conditions that existed in the early Universe and the utilisation of the nuclear energy are discussed.

Nuclear Science Abstracts

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ISBN 13 :
Total Pages : 1058 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis Nuclear Science Abstracts by :

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Particle And Astroparticle Physics, Gravitation And Cosmology: Predictions, Observations And New Projects - Proceedings Of The Xxx-th International Workshop On High Energy Physics

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Publisher : World Scientific
ISBN 13 : 9814689319
Total Pages : 380 pages
Book Rating : 4.8/5 (146 download)

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Book Synopsis Particle And Astroparticle Physics, Gravitation And Cosmology: Predictions, Observations And New Projects - Proceedings Of The Xxx-th International Workshop On High Energy Physics by : Roman Anatolievich Ryutin

Download or read book Particle And Astroparticle Physics, Gravitation And Cosmology: Predictions, Observations And New Projects - Proceedings Of The Xxx-th International Workshop On High Energy Physics written by Roman Anatolievich Ryutin and published by World Scientific. This book was released on 2015-06-16 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique volume captures the content of the XXXth International Workshop on High Energy Physics. The scope of this volume is much wider than just high-energy physics; it actually concerns and includes materials from all the most fundamental areas of modern physics research: high-energy physics proper, gravitation and cosmology. Presentations embrace both theory and experiment.

Spin 96 - Proceedings Of The 12th International Symposium On High-energy Spin Physics

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Publisher : World Scientific
ISBN 13 : 9814546437
Total Pages : 906 pages
Book Rating : 4.8/5 (145 download)

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Book Synopsis Spin 96 - Proceedings Of The 12th International Symposium On High-energy Spin Physics by : J E J Oberski

Download or read book Spin 96 - Proceedings Of The 12th International Symposium On High-energy Spin Physics written by J E J Oberski and published by World Scientific. This book was released on 1997-04-15 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments using highly polarized intense beams and targets, and theoretical studies of spin and polarization phenomena, are now providing us with numerous additional details of the electroweak and strong interactions and the structure of matter. The spin structure of the nucleon has been measured over wide ranges of kinematic variables, and the cross sections have been calculated to several orders in perturbative field theory. At present, the influence of the higher twist contributions, the gluon spin, and the quark orbital angular momentum are under scrutiny. Quantum chromodynamics (QCD) captures a lot of our experimental knowledge of hard polarized scattering processes. Can our understanding of such processes within QCD be further improved?Hyperons produced in high energy reactions show how puzzling strong interactions between hadrons still are. Spin observables in experiments at intermediate energy are used to test parity and charge symmetries. Will they also reveal, at low energy, a violation of time reversal symmetry? We are on the verge of using parity violation measurements at intermediate electron scattering energies to determine the amount of strange quark contributions to the neutral weak form factor of the nucleon. The polarization of the sea quarks is expected to be measured soon in W± decays produced in high energy polarized proton interactions. Will the jets in polarized Z⁰ decays show a definite handedness? These and many other topics are discussed in these proceedings.

Hadron Collider Physics 2002

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Publisher : Springer Science & Business Media
ISBN 13 : 9783540009955
Total Pages : 572 pages
Book Rating : 4.0/5 (99 download)

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Book Synopsis Hadron Collider Physics 2002 by : Martin Erdmann

Download or read book Hadron Collider Physics 2002 written by Martin Erdmann and published by Springer Science & Business Media. This book was released on 2003 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: I Opening Review on Hadron-Collider Physics.- Hadron Colliders, the Standard Model, and Beyond.- 1 What is the Standard Model?.- 2 Hadron Colliders and the Standard Model.- 2.1 Precision electroweak.- 2.2 CKM.- 2.3 Top quark.- 2.4 Higgs boson.- 2.5 QCD.- 3 Beyond the Standard Model.- 3.1 Direct evidence.- 3.2 Indirect evidence.- References.- II Status of the Accelerators and Detectors.- Tevatron Collider Run II Status.- 1 Introduction.- 2 Overview.- 3 Run II Milestones.- 4 Parameters.- 5 Performance to Date.- 6 Accomplishments.- 6.1 Accomplishments: Helix Adjustments.- 6.2 Accomplishments: Antiproton Emittance.- 6.3 Accomplishments: Tevatron Injection Closure.- 7 Outstanding Issues.- 8 Future Prospects.- 9 Reliability.- 10 Summary.- 11 Acknowledgements.- Status of CDF II and Prospects for Run II.- 1 Introduction.- 2 The CDF II Detector and Trigger Upgrades.- 3 Physics Results and Prospects.- 4 Conclusions.- References.- Status of the D Detector.- 1 Introduction.- 2 Overview.- 3 Silicon Vertex Detector.- 4 Central Fiber Tracker.- 5 Calorimeters.- 6 Muon Detectors.- 7 Forward Proton Detectors.- 8 Trigger and Data Acquisition.- 9 Conclusions.- References.- III Standard Model Processes: Parton Luminosities, QCD Evolution.- The Proton Structure as Measured at HERA.- 1 Introduction.- 2 NC Cross Sections in the Complete Kinematic Plane.- 3 High-Q2 Measurements.- 4 Charged Current Measurements.- 5 Summary and Outlook.- References.- Global Fits of Parton Distributions.- 1 Introduction.- 2 Parton Uncertainties.- 2.1 Hessian (Error Matrix) approach.- 2.2 Offset method.- 2.3 Statistical approach.- 2.4 Lagrange multiplier method.- 2.5 Results.- 3 Theoretical Errors.- 3.1 Problems in the fit.- 3.2 Types of Theoretical Error, NNLO.- 3.3 Empirical approach.- 4 Conclusions.- References.- Low x Physics at HERA.- 1 Introduction.- 2 Formalism and Theory.- 3 Results.- 3.1 Inclusive measurements.- 3.2 Exclusive results.- 4 Summary.- References.- Saturation Effects in Hadronic Cross Sections.- 1 Introduction.- 2 The Loop-Loop Correlation Model.- 3 Saturation in Proton-Proton Scattering.- 4 Gluon Saturation.- 5 Conclusion.- References.- IV Standard Model Processes: QCD at High pt.- Progress in NNLO Calculations for Scattering Processes.- 1 Why NNLO Calculations are Important.- 1.1 Renormalisation scale uncertainty.- 1.2 Factorisation scale dependence.- 1.3 Jet algorithms.- 1.4 Transverse momentum of the incoming partons.- 1.5 Power corrections.- 1.6 The shape of the prediction.- 1.7 Parton densities at NNLO.- 2 Recent Progress in the Field.- 3 What Remains to be Done.- References.- Heavy Flavour Production at D .- 1 Introduction.- 2 b-production Cross-section.- 2.1 Muon and Jet Cross-section.- 2.2 b-tagging.- 3 J/? Cross-section.- 4 Other Measurements.- References.- Heavy Quark Production at CDF.- 1 Introduction.- 2 Beauty Production at CDF.- 2.1 CDF Run I results.- 2.2 Preliminary results from CDF Run II.- 3 Quarkonia Production at CDF.- 4 Charm Production at CDF.- 4.1 Run I results.- 4.2 Run II charm production cross-sections.- 5 Conclusion.- References.- Heavy Quark Production at HERA.- 1 Introduction.- 2 Open Charm Production.- 3 Charmonium.- 4 Beauty Production.- 5 Summary.- References.- Theoretical Developments on Hard QCD Processes at Colliders.- 1 Introduction.- 2 Heavy Quarks.- 2.1 Total Cross Sections.- 2.2 Transverse Momentum Distributions.- 2.3 Top Quark Spin Correlations.- 3 Jets.- 3.1 Jet Definitions.- 3.2 Precision Jet Physics.- 3.3 Multiparton Processes.- 4 Photons and Massive Gauge Bosons.- 4.1 Isolated Photons.- 4.2 Photon Pairs.- 4.3 Vector Boson and Higgs Production.- 4.4 Transverse Momentum Distributions.- 5 Conclusions and Outlook.- References.- Jet Production at CDF.- 1 Introduction.- 2 Inclusive Jet Production.- 3 Three-jet Production.- 4 Study of Jet Shapes in Run 2.- 5 Study of the Underlying Event.- 6 Study of W+Njet Production.- References.- Jet Algorithms at D .- 1 Introduction.- 2 The Measurement of Jets.- 3 Run I Co

Intersections of Particle and Nuclear Physics

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Publisher : American Inst. of Physics
ISBN 13 : 9780735401693
Total Pages : 884 pages
Book Rating : 4.4/5 (16 download)

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Book Synopsis Intersections of Particle and Nuclear Physics by : Zohreh Parsa

Download or read book Intersections of Particle and Nuclear Physics written by Zohreh Parsa and published by American Inst. of Physics. This book was released on 2004-03-09 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this meeting, as with the seven previous conferences in this series, was to bring together particle and nuclear physicists to share scientific reports and discuss areas of research which overlap both their disciplines. Its relevance has steadily grown as the areas of overlap between particle and nuclear physics have increased. In addition, the success of the standard model has provided a common underpinning for both disciplines as well as similar fundamental goals. Indeed, Quantum Chromodynamics (QCD) has proven to be "the" theory of strong interactions. As such, it forms the basis for nuclear physics as well as high energy hadronic interactions. Topics included are: QCD spectroscopy and dynamics, relativistic heavy ions, QCD and nuclear structure, lepton-hadron and hadron-hadron scattering, heavy quark and heavy lepton physics, spin physics, nuclear and particle astrophysics, neutrinos, accelerators, facilities and detectors, as well as tests of fundamental symmetries.

Physics In Collision Xix, Procs

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Publisher : World Scientific
ISBN 13 : 9814492809
Total Pages : 389 pages
Book Rating : 4.8/5 (144 download)

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Book Synopsis Physics In Collision Xix, Procs by : Myron Campbell

Download or read book Physics In Collision Xix, Procs written by Myron Campbell and published by World Scientific. This book was released on 2000-07-27 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: The XIX Physics in Collision conference reviewed experimental results in electroweak, quantum chromodynamics, neutrino, bottom and rare kaon physics, and updated recent developments in the area of gamma ray bursts as well as the issue of the cosmological constant and dark matter.The conference opened with reports on electroweak physics. A decade of precision experiments in laboratories around the world failed to uncover any significant deviations from standard model predictions. Precise W boson and top quark mass measurements suggest a low mass Higgs boson in the standard model, possibly within the reach of the LEP II and the upgraded Tevatron colliders. These presentations were followed by a summary of the latest results on searches for Higgs and supersymmetry.There were three reports on neutrino physics: atmospheric, solar and reactor/accelerator based neutrino experiments and results. Impressive Super-K results strongly suggest νμ→νς oscillation, a scenario confirmed by less precise Soudan2 and MACRO data.The latest results on strange and heavy quark physics were summarized. High statistics from CLEO, LEP I and Tevatron have enabled experimenters to study many rare charm and bottom quark decays for the first time. Among many other interesting results presented, the first measurements of sin 2β by CDF and ε′/ε by KTeV provide a preview of expected developments in the near future.

Scientific and Technical Aerospace Reports

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Publisher :
ISBN 13 :
Total Pages : 286 pages
Book Rating : 4.:/5 (3 download)

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Book Synopsis Scientific and Technical Aerospace Reports by :

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1977 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Energy Research Abstracts

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Publisher :
ISBN 13 :
Total Pages : 472 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis Energy Research Abstracts by :

Download or read book Energy Research Abstracts written by and published by . This book was released on 1993-08 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Physics in Collision 19

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Publisher : World Scientific
ISBN 13 : 9789810243548
Total Pages : 398 pages
Book Rating : 4.2/5 (435 download)

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Book Synopsis Physics in Collision 19 by : M. Campbell

Download or read book Physics in Collision 19 written by M. Campbell and published by World Scientific. This book was released on 2000 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: The XIX Physics in Collision conference reviewed experimental results in electroweak, quantum chromodynamics, neutrino, bottom and rare kaon physics, and updated recent developments in the area of gamma ray bursts as well as the issue of the cosmological constant and dark matter.The conference opened with reports on electroweak physics. A decade of precision experiments in laboratories around the world failed to uncover any significant deviations from standard model predictions. Precise W boson and top quark mass measurements suggest a low mass Higgs boson in the standard model, possibly within the reach of the LEP II and the upgraded Tevatron colliders. These presentations were followed by a summary of the latest results on searches for Higgs and supersymmetry.There were three reports on neutrino physics: atmospheric, solar and reactor/accelerator based neutrino experiments and results. Impressive Super-K results strongly suggest ????? oscillation, a scenario confirmed by less precise Soudan2 and MACRO data.The latest results on strange and heavy quark physics were summarized. High statistics from CLEO, LEP I and Tevatron have enabled experimenters to study many rare charm and bottom quark decays for the first time. Among many other interesting results presented, the first measurements of sin 2? by CDF and î?/î by KTeV provide a preview of expected developments in the near future.