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Precise predictions for B -> Xs l+ l- in the large q2 region

Description: The inclusive B -> Xs l+ l- decay rate in the large q2 region (q2> m_psi'2) receives significant nonperturbative corrections. The resulting uncertainties can be drastically reduced by normalizing the rate to the B -> Xu l nu rate with the same q2 cut, which allows for much improved tests of short distance physics. We calculate this ratio, including the order 1/m_b3 nonperturbative corrections and the analytically known NNLO perturbative corrections. Since in the large q2 region an … more
Date: July 12, 2007
Creator: Ligeti, Zoltan; Ligeti, Zoltan & Tackmann, Frank J.
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Partner: UNT Libraries Government Documents Department
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Unraveling duality violations in hadronic tau decays

Description: There are some indications from recent determinations of the strong coupling constant alpha_s and the gluon condensate that the Operator Product Expansion may not be accurate enough to describe non-perturbative effects in hadronic tau decays. This breakdown of the Operator Product Expansion is usually referred to as being due to"Duality Violations." With the help of a physically motivated model, we investigate these duality violations. Based on this model, we argue how they may introd… more
Date: March 3, 2008
Creator: Cata, Oscar; Cata, Oscar; Golterman, Maarten & Peris, Santiago
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Partner: UNT Libraries Government Documents Department
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Semileptonic Decays and Sides of the Unitarity Triangle

Description: The elements of the CKM matrix enter the expressions for the decay rates and mixing amplitudes of hadrons. In some cases, the theoretical expressions are free of strong interaction effects, for example the CP asymmetry in B {yields} J/{psi} K{sub S}{sup 0}, so that measuring the CP asymmetry directly gives the value of sin 2{beta}, with the error in the result given by the experimental error in the measurement. In most cases, however, the experimentally measured quantities depend on strong inte… more
Date: May 1, 2003
Creator: Ligeti, Zoltan; Bauer, C.; Bernard, C.; Bigi, I.; Datta, M.; del Re, D. et al.
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Partner: UNT Libraries Government Documents Department
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A Study of Semileptonic B Decays And of Lepton Flavor Violating Tau Decays at BaBar

Description: The study of the semileptonic B decays at BABAR is presented. The results shown include measurements of the moments of hadronic-mass and electron-energy of the decay B {yields} X{sub c}{ell}{nu}; a determination of the |V{sub cb}| CKM matrix element and other heavy quark parameters from a simultaneous fit to the moments using kinetic scheme of Operator Product Expansion; a measurement of the inclusive branching fraction of B {yields} X{sub u}{ell}{nu} and determination of |V{sub ub}|. The most … more
Date: June 10, 2005
Creator: Igonkina, O. & U., /Oregon
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Introduction to heavy meson decays and CP asymmetries

Description: These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B dec… more
Date: February 5, 2003
Creator: Ligeti, Zoltan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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HADRONIC SCATTERING IN THE COLOR GLASS CONDENSATE.

Description: Multi-particle production in QCD is dominated by higher twist contributions. The operator product expansion is not very effective here because the number of relevant operators grow rapidly with increasing twist. The Color Glass Condensate (CGC) provides a framework in QCD to systematically discuss ''classical'' (multiple scattering) and ''quantum'' evolution (shadowing) effects in multi-particle production. The apparently insuperable problem of nucleus-nucleus scattering in QCD simplifies great… more
Date: May 15, 2005
Creator: Venugopalan, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Introduction to heavy meson decays and CP asymmetries

Description: These lectures are intended to provide an introduction to heavy meson decays and CP violation. The first lecture contains a brief review of the standard model and how the CKM matrix and CP violation arise, mixing and CP violation in neutral meson systems, and explanation of the cleanliness of the sin 2{beta} measurement. The second lecture deals with the heavy quark limit, some applications of heavy quark symmetry and the operator product expansion for exclusive and inclusive semileptonic B dec… more
Date: February 5, 2003
Creator: Ligeti, Zoltan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Comments on Worldsheet Theories Dual to Free Large N Gauge Theories

Description: We continue to investigate properties of the worldsheet conformal field theories (CFTs) which are conjectured to be dual to free large N gauge theories, using the mapping of Feynman diagrams to the worldsheet suggested in [1]. The modular invariance of these CFTs is shown to be built into the formalism. We show that correlation functions in these CFTs which are localized on subspaces of the moduli space may be interpreted as delta-function distributions, and that this can be consistent with a l… more
Date: March 21, 2007
Creator: Aharony, Ofer; /Weizmann Inst. /Stanford U., ITP /SLAC; David, Justin R.; Gopakumar, Rajesh; Inst., /Harish-Chandra Res.; Komargodski, Zohar et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Precision Studies of Duality in the 't Hooft Model

Description: The authors address numerical aspects of local quark-hadron duality using the example of the exactly solvable 't Hooft model, two-dimensional QCD with Nc ?8. The primary focus of these studies is total semileptonic decay widths relevant for extracting (Vcb) and (Vub). They compare the exact channel-by-channel sum of exclusive modes to the corresponding rates obtained in the standard 1/mQ expansion arising from the Operator Product Expansion. An impressive agreement sets in unexpectedly early, i… more
Date: June 1, 2000
Creator: Lebed, R.F. & Uraltsev, N.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Moments of Structure Functions in Full QCD

Description: Moments of the quark density distribution, moments of the quark helicity distribution, and the tensor charge are calculated in full QCD. Calculations of matrix elements of operators from the operator product expansion have been performed on 16{sup 3} x 32 lattices for Wilson fermions at {beta} = 5.6 using configurations from the SESAM collaboration and at {beta} = 5.5 using configurations from SCRI. One-loop perturbative renormalization corrections are included. Selected results are compared wi… more
Date: August 1, 2000
Creator: Dolgov, D.; Brower, R.; Capitani, S.; Negele, J. W.; Pochinsky, A.; Renner, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Moments of Nucleon Light Cone Quark Distributions Calculated in Full Lattice QCD

Description: Moments of the quark density, helicity, and transversity distributions are calculated in unquenched lattice QCD. Calculations of proton matrix elements of operators corresponding to these moments through the operator product expansion have been performed on the 16{sup 3} x 32 lattices for Wilson fermions at Beta=5.6 using configurations from the SESAM collaboration and at Beta = 5.5 using configurations from SCRI. One-loop perturbative renormalization corrections are included. At quark masses a… more
Date: January 1, 2002
Creator: Dolgov, D.; Brower, R.; Capitani, S.; Dreher, P.; Negele, J.W.; Pochinsky, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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