Scattering Meson and Baryon Resonances in Lattice QCD PDF Download

Author: Srijit Paul
Publisher:
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Category :
Languages : en
Pages :

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Author:
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ISBN:
Category :
Languages : en
Pages : 27

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Book Description
The??+,?+?°, K+p, K+n, {bar K}°?+, and {bar K}°?° scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find a{sub {pi}+?+} = -0.197 ± 0.017 fm, and a{sub {pi}+?°} = -0.098 ± 0.017 fm, where the comprehensive error includes statistical and systematic uncertainties.

Author:
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Languages : en
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There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems.

Author:
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Languages : en
Pages : 81

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Lüscher's method is routinely used to determine meson-meson, meson-baryon, and baryon-baryon s-wave scattering amplitudes below inelastic thresholds from lattice QCD calculations--presently at unphysical light-quark masses. In this work we review the formalism and develop the requisite expressions to extract phase shifts describing meson-meson scattering in partial waves with angular momentum l≤6 and l=9. The implications of the underlying cubic symmetry, and strategies for extracting the phase shifts from lattice QCD calculations, are presented, along with a discussion of the signal-to-noise problem that afflicts the higher partial waves.

Author:
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Languages : en
Pages : 12

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We perform a non-perturbative lattice calculation of the P-wave pion-pion scattering phase in the rho-meson decay channel using two flavors of maximally twisted mass fermions at pion masses ranging from 480 MeV to 290 MeV. Making use of finite-size methods, we evaluate the pion-pion scattering phase in the center-of-mass frame and two moving frames. Applying an effective range formula, we find a good description of our results for the scattering phase as a function of the energy covering the resonance region. This allows us to extract the rho-meson mass and decay width and to study their quark mass dependence.

Author: A. V. Anisovich
Publisher: World Scientific
ISBN: 9812818251
Category : Science
Languages : en
Pages : 603

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This book is devoted to the investigation of the strongly interacting hadrons ? to a quark model operating with effective color particles, constituent quarks, massive effective gluons and diquarks. The study of strong interactions based on effective constituent particles requires a solid ground of experimental data, which we now have at our disposal with the serious progress made in the investigation of hadrons, especially meson states.The present understanding of QCD applied to strong interactions can be distorted by prejudices. Therefore, the way followed by the quark model is to rely on the experiment and to restore the effective Hamiltonian on the basis of QCD on the one hand, and, on the other, of the spectral integral method.Baryon-baryon and antibaryon-baryon interactions are studied with the purpose of unambiguous applications of the written formulae to the interpretation of experimental data ? to the observation of new meson and baryon resonances. The technique used is the spin-orbital momentum expansion of the amplitude. This method is our basic approach to the proper treatment of experimental data. The photon-induced reactions are also considered and the problem of form factors is discussed.

Author: W Melnitchouk
Publisher: World Scientific
ISBN: 9814490105
Category : Science
Languages : en
Pages : 345

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This volume is centered on recent developments in the exploration of hadronic structure through lepton scattering, in the description of hadron physics directly from lattice QCD and non-perturbative QCD models, and in efforts to strengthen the links between these activities. Specific topics that are covered include: parton distribution functions, polarized structure functions, generalized structure functions, nuclear effects, quark-hadron duality, electromagnetic form factors, structure functions and hadron properties from lattice QCD, and QCD models based on the Dyson-Schwinger equations.

Author: Huey-Wen Lin
Publisher: Springer
ISBN: 3319080229
Category : Science
Languages : en
Pages : 255

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With ever increasing computational resources and improvements in algorithms, new opportunities are emerging for lattice gauge theory to address key questions in strongly interacting systems, such as nuclear matter. Calculations today use dynamical gauge-field ensembles with degenerate light up/down quarks and the strange quark and it is possible now to consider including charm-quark degrees of freedom in the QCD vacuum. Pion masses and other sources of systematic error, such as finite-volume and discretization effects, are beginning to be quantified systematically. Altogether, an era of precision calculation has begun and many new observables will be calculated at the new computational facilities. The aim of this set of lectures is to provide graduate students with a grounding in the application of lattice gauge theory methods to strongly interacting systems and in particular to nuclear physics. A wide variety of topics are covered, including continuum field theory, lattice discretizations, hadron spectroscopy and structure, many-body systems, together with more topical lectures in nuclear physics aimed a providing a broad phenomenological background. Exercises to encourage hands-on experience with parallel computing and data analysis are included.

Author: Thibaut Métivet
Publisher:
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Category :
Languages : en
Pages : 0

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The formalism of Quantum Chromodynamics on the lattice (or Lattice QCD) allows to perform ab-initio non-perturbative studies of strong-interaction driven processes, as it provides both a covariant regularisation of the theory of QCD and a natural framework for numerical computations. In this work, after a review of the main features of QCD and a step-by-step presentation of our discretization of QCD on a lattice, we undertake detailed studies of two problems of hadronic physics: the phenomenon of resonant scattering and the structure of the nucleon. The lattice calculations are performed with the Budapest-Marseille-Wuppertal Collaboration's 2+1-flavour gauge configurations, which give access to a wide range of lattice spacings, volumes and quarks masses, thereby allowing to study the sensibility of our results on these parameters, and to perform a complete continuum extrapolation. These configurations include dynamical quarks, and use a clover-improved Wilson QCD action. To investigate the scattering of particles on the lattice, we set up a Lüscher analysis for the emblematic case of pion-pion scattering in the channel of the rho meson resonance. We analyse our data with a variational generalized eigenvalue method, and give an in-depth calculation of the scattering phase-shifts and the corresponding resonance parameters, with a full control of the systematic errors. Our results provide an important step for lattice studies of scattering states, as they are the first to be performed at the physical pion mass, where one can see the actual decay of the rho into two pions. The obtained rho meson parameters are in good agreement with the experimental values, and consistent with a weak pion mass dependence of the coupling between the rho and two pions. As for our probe of the structure of the nucleon, we present a complete extraction of the electroweak isovector form factors, with a comprehensive study of the electric charge squared radius and of the axial charge. Our analysis also feature data at the physical pion mass, which turns out to be crucial in order to perform safe extrapolations to the physical point, as the chiral perturbation theory predicts violent variations of these quantities near the massless-quarks point. Our calculation includes source and sink projections onto the nucleon state, as well as a combined fit method between the two-point and three-point correlation functions to control the contamination of our data by excited states. Although one would need more data to perform a high-accuracy determination of the nucleon radius and axial charge at the physical point with a relevant estimation of the systematic errors, the results we obtain are in good agreement with the experiment and suggest that the excited-state effects are under control. Our analysis also highlights that gauge configurations ensembles near the physical pion mass and with large volumes must be used in order to extract accurate information about the nucleon structure from lattice calculations.

Author: Wally Melnitchouk
Publisher: World Scientific
ISBN: 9789812799708
Category : Science
Languages : en
Pages : 352

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Book Description
This volume is centered on recent developments in the exploration of hadronic structure through lepton scattering, in the description of hadron physics directly from lattice QCD and non-perturbative QCD models, and in efforts to strengthen the links between these activities. Specific topics that are covered include: parton distribution functions, polarized structure functions, generalized structure functions, nuclear effects, quark-hadron duality, electromagnetic form factors, structure functions and hadron properties from lattice QCD, and QCD models based on the DysonOCoSchwinger equations. Contents: Partonic Structure of Hadrons: Chiral Extrapolation of Lattice Structure Function Calculations (W Detmold); Exclusive Processes at HERMES (N Bianchi); Soft Pion Production Associated with Deeply Virtual Compton Scattering (L Mosse); Spin Structure of Hadrons: Polarized Structure Functions in QCD (J Kodaira); Single Spin Asymmetries and Quark Fragmentation (M Anselmino et al.); Perturbative OCo Nonperturbative QCD Transition: Lepton Scattering and Quark-Hadron Duality Studies at Jlab (R Ent); Estimating Low Energy Model Parameters from Deep Inelastic Scattering (L P Hoyt & A I Signal); Form Factors: Physical Hadron Properties from Lattice Data at Large Quark Masses (A W Thomas); Electromagnetic Interactions in Light Front Dynamics (J -F Mathiot); Nucleon Form Factors in the Covariant Diquark-Quark Model (R Alkofer & M Oettel); Hadron Excitations, Confinement and Chiral Symmetry Breaking: Experimental Studies of the Hadron Spectrum (J Napolitano); The Character of Goldstone Bosons (M B Hecht et al.); Deconfining by Winding (R Hofmann); Small- x Physics and Nuclear Medium Effects: Leading Nucleon Production at HERA (G Levman); Nuclear Medium Effects at HERMES (P di Nezza); Physics Motivation for a Polarized Electron-Ion Collider (J M Cameron & J T Londergan); and other papers. Readership: Theoretical and experimental researchers in nuclear and high energy physics."