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Showing 1 to 20 of 24 for “"quark-antiquark"”.
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Paarproduktion schwerer Quarks in e+ e- -Kollisionen: QCD-Strahlungskorrekturen für die Quark-Antiquark-Beiträge zur Ordnung alpha s 2
… amplitude of a virtual Z-boson into a heavy quark anti-quark pair is decomposed into four dimensionless form factors which are extracted from the decay amplitude with appropriate projectors. The resulting 1- and 2-loop integrals are reduced to linear combinations of known master integrals …
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Perturbative Check of the Action and Energy Lattice Sum Rules
… The action sum rule gives a relation between the quark-antiquark potential, its logarithmic derivative with respect to distance and the expectation value of the action; the energy sum rule expresses the potential as the sum of the energy in the gluon fields and of an anomalous term. Two different …
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Spectroscopy of exotic charm mesons from lattice QCD
… mesons are mesons that cannot be described as a quark-antiquark pair. The number of exotic mesons has been growing every year in the charm sector and the theoretical understanding of them is often conflicted amongst the community. Some possible explanations include hybrid mesons where the …
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Diffraction in electron-proton collisions
… cross section for diffractive production of a quark-antiquark pair from a real or virtual photon. This allows us to give detailed predictions for diffractive electro- or photoproduction of a jet pair, for diffractive charm production, and for the inclusive cross section in diffractive deep …
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The Static Quark Potential at Finite Temperature and Density
… the potential energy between an infinitely heavy quark-antiquark pair at high temperatures and densities. The calculations are carried out via lattice QCD in conjunction with a recently developed Bayesian inference method. We provide a detailed overview lattice QCD, Bayesian infer- ence methods …
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Numerical tests of dual superconductivity in non-abelian lattice gauge theories
… procedure for determining the part of the quark-antiquark potential produced by magnetic currents is then developed. The computer algorithms required to perform these numerical tests are then discussed as well as the results of the project. Finally, I present further supporting evidence …
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Soft diffractive high energy scattering and form factors in nonperturbative QCD
… vacuum. We describe mesons in a simple quark-antiquark picture, for baryons we assume a quark-diquark structure, as hadronic wave functions we apply a Wirbel-Stech-Bauer ansatz. In the following we calculate integrated and differential cross sections from the scattering amplitudes, as …
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Heavy quarks in the initial stages of proton-ion collisions [I quark pesanti negli stati iniziali delle collisioni protone-ione]
… l’effetto di tali campi sulla dinamica dei quark pesanti (charm e beauty), che vengono prodotti e si evolvono in questo mezzo. L’influenza dei campi iniziali del glasma sui quark pesanti è risultata piuttosto rilevante: in particolare, osserviamo che il glasma provoca un tasso di …
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Linear Sigma Models in QCD and S3 Symmetry for Neutrinos
… model which contains two scalar nonets (one of quark-antiquark type and the other of diquark-antidiquark type) and two corresponding pseu- doscalar nonets. It is shown that a reasonable agreement with experimental data is obtained up to about 1 GeV. Some comparison is made to the situation in …
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Measurement of the Beam Asymmetry for the ETA and ETA Prime Mesons with the Gluex Experiment
… aims to provide evidence of hybrid mesons, quark-antiquark pairs with gluonic excitations, which are predicted by quantum chromodynamics calculations on the lattice. GlueX features a linearly-polarized photon beam incident on a liquid hydrogen target and a nearly-four-pi hermetic detector …
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From Static Potentials to High-Energy Scattering
… theorems to show consistency with the static quark-antiquark potential. We generalize Meggiolaro's analytic continuation from parton-parton to dipole-dipole scattering and obtain a Euclidean approach to high-energy scattering that allows us in principle to calculate S-matrix elements in …
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Quarkonium Suppression in pPb Collisions at CMS and Timing Detectors for Future Collider Experiment
… has firmly established the existence of the quark–gluon plasma (QGP), yet recent experimental results suggest that QGP-like phenomena may also emerge in smaller systems such as pp and pPb collisions. Quarkonium, bound states of heavy quark–antiquark pairs, provide sensitive probes in this …
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Exotic States in Quarkonium Physics: Effective Theories of Heavy Mesonic Molecules and an AdS/QCD Model of Hybrid Quarkonium
<p>Quantum chromodynamics (QCD), the theory of quarks and gluons, is known to be</p><p>the correct description of strong nuclear interactions. At high energy and momenta,</p><p>one can use QCD directly to compute quantities of physical interest related to the</p><p>strong force. At low energies and …
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Thomas Fermi model for mesons and new noise subtraction techniques in lattice QCD.
Lattice QCD calculations of quark loop operators are extremely time-consuming to evaluate. To calculate these diagrams we use stochastic noise methods, which employ a randomly generated set of noise vectors to project out physical signals. This is done with linear equation solvers like GMRES-DR …
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Strongly coupled plasmas and the QCD critical point
… begin our investigation of the properties of quarks and baryons which live in the strongly coupled plasma of certain gauge theories which are similar to QCD using the AdS/CFT correspondence. We first study the velocity dependence of the screening length, L,, of Nc quarks arranged in a circle …
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Determination of the X(3872) Meson Quantum Numbers
… the well established mesons consisting of quark-antiquark pairs (qq-bar), it has been proposed that "exotic" qqq-barq-bar mesons could exist. One of the candidates for a four-quark state is the charmonium-like state X(3872) which was first observed by the Belle experiment in 2003. This …
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Bestimmung der Masse und Breite des W-Bosons im semileptonischen Zerfallskanal mit dem OPAL Detektor bei LEP
… bei denen ein W-Boson hadronisch in ein Quark-Antiquark-Paar zerfällt und das andere in ein geladenes Lepton und ein Neutrino. In der Faltungsmethode werden die aus der Detektorauflösung resultierenden Fehler der einzelnen Ereignisse berücksichtigt. Dazu wird eine Funktion P(m) für jedes …
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Reps for JIMWLK: applications of representation theory to a novel approach to the JIMWLK equation
… matrix used in the JIMWLK evolution of two quark-antiquark pairs are bounded by the unit circle.
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Transport coefficients in quantum chromodynamics
… to find the transport coefficients for quark and gluon systems. Most authors use the relaxation time approximation of the Boltzmann equation to compute the transport coefficients, but this method has shortcomings in mixtures. We use the Chapman Enskog (CE) method to solve the classical …
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The scattering of spinning hadrons from lattice QCD
… calculation. I work at heavier than physical quark masses at the $\text{SU}(3)_{\text{F}}$ point where the up, down and strange quarks are mass degenerate. Finite-volume spectra are calculated and, utilising the relationship between the discrete energy spectrum and the infinite-volume …
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