Heavy Quark Production and Fragmentation Processes in Next-to-leading Order QCD PDF Download

Author: Stefan Kretzer
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Bradley Cox
Publisher: Springer Science & Business Media
ISBN: 1468488422
Category : Science
Languages : en
Pages : 548

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The Advanced Research Workshop on QeD Hard Hadronic Processes was held on 8-13 October 1987 at Hotel on the Cay, St. Croix, U. S. Virgin Islands. The underlying theme of the workshop, the first in a series, was an examination, both theoretical and experimental, of the state of understanding of Quantum Chromodynamics. Because of the pervasiveness of the strong interactions in all aspects of high energy physics, QCD is central to many problems in elementary particle physics. Therefore, this workshop was organized to provide a forum in which the theory Quantum Chromodynamics cou 1 d be confronted with experi ment. The workshop was organ i zed in four sessions, each of which concentrated on a major experimental arena in which a hard QCD process can be measured experimentally. A fifth session was rlevoted to global issues which effect all QCD processes. Each session began with a survey of the theoretical developments in the particular area and concluded with a round table which discussed the various information presented in the course of the discussions. A session of the workshop was devoted to the direct production of high transverse momentum photons in hadronic interactions. Data from several experiments, either completed or in progress at CERN (NA3, NA24, WA70, UA6, CCOR, R806, AFS, RllO, UA1 and UA2), were di scussed and the prospects for two new upcomi ng experi ments from Fermil ab (E-705, E-706) were presented.

Author:
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Category :
Languages : en
Pages : 6

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We extend the phase space slicing method to allow for heavy quarks and fragmentation functions. The method can be used to calculate differential cross section in which any particular particle (massive or massless) is tagged. 4 refs.

Author: Xiaoning Wang
Publisher:
ISBN:
Category : Quantum chromodynamics
Languages : en
Pages : 300

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Author:
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ISBN:
Category :
Languages : en
Pages : 12

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The fragmentation functions for gluons to split into P-wave heavy quarkonium states are calculated to leading order in the QCD coupling constant. Long-distance effects are factored into two nonperturbative parameters: the derivative of the radial wavefunction at the origin and a second parameter related to the probability for a heavy-quark-antiquark pair that is produced in a color-octet S-wave state to form a color-singlet P-wave bound state. The fragmentation probabilities for a high transverse momentum gluon to split into the P-wave charmonium states \chi_{c0}, \chi_{c1}, and \chi_{c2} are estimated to be 0.4 \times 10{̂-4}, 1.8 \times 10{̂-4}, and 2.4 \times 10{̂-4}, respectively. This fragmentation process may account for a significant fraction of the rate for the inclusive production of \chi_{cJ} at large transverse momentum in p \bar p colliders.

Author: Mohammad Assadsolimani
Publisher: disserta Verlag
ISBN: 3954256746
Category : Science
Languages : en
Pages : 161

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It is known that the LHC has a considerable discovery potential because of its large centre-of-mass energy (vs =14 TeV) and the high design luminosity. In addition, the two experiments ATLAS and CMS perform precision measurements for numerous models in physics. The increasing experimental precision demands an even higher level of accuracy on the theoretical side. For a more precise prediction of outcomes, one has to consider the corrections obtained typically from Quantum Chromodynamics (QCD). The calculation of these corrections in the high energy regime is described by perturbation theory. In the present study, multi-loop calculations in QCD, including in particular two-loop corrections for single top quark production, are considered. There are several phenomenological motivations to study single top quark production: Firstly, the process is sensitive to the electroweak Wtb-vertex; moreover, non-standard couplings can hint at physics beyond the Standard Model. Secondly, the t-channel cross section measurement provides information on the b-quark Parton Distribution Functions (PDF). Finally, single top quark production enables us to directly measure the Cabibbo-Kobayashi-Maskawa(CKM) matrix element Vtb. The next-to-next-to-leading-order (NNLO) calculation of the single top quark production has many building blocks. In this study, two blocks will be presented: one-loop corrections squared and two-loop corrections interfered with Born. Initially, the one-loop squared contribution at NNLO for single top quark production will be calculated. Before we begin with the calculation of the two-loop corrections to single top quark production, we calculate the QCD form factors of heavy quarks at NNLO, along with the axial vector coupling as a first independent check. A comparison with the relevant literature suggests that this approach is in line with generally accepted procedure. This consistency check provides a proof of the validity of our setup. In the next step, the two-loop corrections to single top quark production will be calculated. After reducing all occurring tensor integrals to scalar integrals, we apply the integration by parts method (IBP) to find the master integrals. This step is a major challenge compared to all similar calculations because of the number of variables in the problem (two Mandelstam variables s and t, the dimension d and the mass of the top quark mt as well as the mass of the W boson mw). Finally, the calculation of the three kinds of topologies – vertex corrections, double boxes and non-planar double boxes – in the two-loop contribution at NNLO calculation will be presented.

Author: J. Thanh Van Tran
Publisher: Atlantica Séguier Frontières
ISBN: 9782863322048
Category : Hadron interactions
Languages : en
Pages : 704

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Author: R. K. Ellis
Publisher: Cambridge University Press
ISBN: 9780521545891
Category : Science
Languages : en
Pages : 462

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A detailed overview of the physics of high-energy colliders emphasising the role of QCD.

Author: J. Thanh Van Tran
Publisher: Atlantica Séguier Frontières
ISBN: 9782863321188
Category : Hadron interactions
Languages : en
Pages : 586

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Author: L. Cifarelli
Publisher: Springer Science & Business Media
ISBN: 1461534402
Category : Science
Languages : en
Pages : 291

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This volume contains the Proceedings of the 17th Workshop of the INFN ELOISATRON Project on "QCD at 200 TeV", held at the "Ettore Majorana" Centre for Scientific Culture, EMCSC, Erice, Trapani, Italy, in the period 11-17 June 1991. The new multi-Te V frontiers of Subnuclear Physics are no more beyond our imagination. A conceptual design of the highest energy (100+100 TeV) proton-proton collider -the ELOISA TRON -already exists. Intensive R & D studies are on the go to develop the most promising and innovative detector technologies for the highest energy and luminosity. QCD (Quantum Chromo-Dynamics) will be the theory to describe the expected Physics scenario of future S upercolliders. The purpose of the Workshop was therefore to review the recent status of QCD in High Energy interactions and to discuss the novel aspects of Perturbative and Non Perturbative QCD with special emphasis on future experimental studies at Super-High Energy Colliders, up to the 200 Te V limit. The topics were: - Classical QCD: particle multiplication, multiplicities and spectra, jet profiles, coherence effects, etc. - Hadron interaction cross-sections and structure functions at Super-High Energies, small-x behaviour, QCD Pomeron, "hot spots"--QCD fragmentation models, present and future. - Artificial neural networks in High Energy Physics. - New theoretical aspects of QCD at Super-High Energies (instanton-induced large cross sections, baryon number violation and peculiar multi-quark production events, etc.)