Download or read book Lattice QCD Determination of States with Spin 5 written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Energies for excited isospin 1/2 states that include the nucleon are computed using quenched, anisotropic lattices. Baryon interpolating field operators that are used include nonlocal operators that provide G2 irreducible representations of the octahedral group. States with spin 5/2 or higher are identified as degenerate energies that occur in irreducible representations of the octahedral group corresponding to the subduction of the continuum spin.
Download or read book Lattice QCD Determination of Patterns of Excited Baryon States written by and published by . This book was released on 2007 with total page 74504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energies for excited isospin I = 1/2 and I = 3/2 states that include the nucleon and Delta families of baryons are computed using quenched, anisotropic lattices. Baryon interpolating field operators that are used include nonlocal operators that provide G2 irreducible representations of the octahedral group. The decomposition of spin 5/2 or higher spin states is realized for the first time in a lattice QCD calculation. We observe patterns of degenerate energies in the irreducible representations of the octahedral group that correspond to the subduction of the continuum spin 5/2 or higher. The overall pattern of low-lying excited states corresponds well to the pattern of physical states subduced to the irreducible representations of the octahedral group.
Download or read book Structure of Nucleon Excited States from Lattice QCD written by Finn M. Stokes and published by Springer Nature. This book was released on 2019-08-20 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum Chromodynamics (QCD) describes the interactions between elementary quarks and gluons as they compose the nucleons at the heart of atomic structure. The interactions give rise to complexity that can only be examined via numerical simulations on supercomputers. This work provides an introduction to the numerical simulations of lattice QCD and establishes new formalisms relevant to understanding the structure of nucleons and their excited states. The research opens with an examination of the non-trivial QCD vacuum and the emergence of “centre domains.” The focus then turns to establishing a novel Parity-Expanded Variational Analysis (PEVA) technique solving the important problem of isolating baryon states moving with finite momentum. This seminal work provides a foundation for future calculations of baryon properties. Implementation of the PEVA formalism discloses important systematic errors in conventional calculations and reveals the structure of nucleon excited states from the first principles of QCD for the first time.
Download or read book Particle Physics Reference Library written by Herwig Schopper and published by Springer Nature. This book was released on 2020 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first open access volume of the handbook series contains articles on the standard model of particle physics, both from the theoretical and experimental perspective. It also covers related topics, such as heavy-ion physics, neutrino physics and searches for new physics beyond the standard model. A joint CERN-Springer initiative, the "Particle Physics Reference Library" provides revised and updated contributions based on previously published material in the well-known Landolt-Boernstein series on particle physics, accelerators and detectors (volumes 21A, B1,B2,C), which took stock of the field approximately one decade ago. Central to this new initiative is publication under full open access
Download or read book Lattice QCD for Nuclear Physics written by Huey-Wen Lin and published by Springer. This book was released on 2014-11-21 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Pentaquark04 Proceedings Of The International Workshop written by Atsushi Hosaka and published by World Scientific. This book was released on 2005-05-06 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers collected in this book represent an exciting contribution to the growing body of experimental and theoretical research into exotic hadrons. The prime focus of the volume is the latest work on pentaquark baryons.The in-depth experimental reports cover both positive and negative evidence for the existence of various combinations of particles, and photo-electro production, hadronic production and high-energy processes are discussed in detail.Important theoretical areas of current interest are considered, including chiral solitons, constituent quarks, the QCD sum rule, lattice QCD, production reactions, and the determination of spin and parity. The volume features the work of two pioneering theorists, H Lipkin and D Diakonov, among the comprehensive coverage of the latest theoretical ideas in the field.The proceedings have been selected for coverage in:• Index to Scientific & Technical Proceedings® (ISTP® / ISI Proceedings)• Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)• CC Proceedings — Engineering & Physical Sciences
Download or read book Hadronic Physics From Lattice Qcd written by Anthony M Green and published by World Scientific. This book was released on 2004-10-07 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particle and nuclear physicists frequently take results from Lattice QCD at their face value without probing into their reliability or sophistication. This attitude usually stems from a lack of knowledge of the field. The aim of the present volume is to rectify this by introducing in an elementary way several topics, which we believe are appropriate for, and of possible interest to, both particle and nuclear physicists who are non-experts in the field.
Download or read book Confinement Duality and Nonperturbative Aspects of QCD written by Pierre van Baal and published by Springer Science & Business Media. This book was released on 2005-12-11 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a NATO ASI and Isaac Newton Institute Workshop held in Cambridge, UK, June 23-July 4, 1997
Download or read book Excited State Effective Masses in Lattice QCD written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We apply black-box methods, i.e. where the performance of the method does not depend upon initial guesses, to extract excited-state energies from Euclidean-time hadron correlation functions. In particular, we extend the widely used effective-mass method to incorporate multiple correlation functions and produce effective mass estimates for multiple excited states. In general, these excited-state effective masses will be determined by finding the roots of some polynomial. We demonstrate the method using sample lattice data to determine excited-state energies of the nucleon and compare the results to other energy-level finding techniques.
Download or read book Formal Developments for Lattice QCD with Applications to Hadronic Systems written by Zohreh Davoudi and published by . This book was released on 2014 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to make reliable predictions with controlled uncertainties for a wide range of nuclear phenomena, a theoretical bottom-up approach, by which hadrons emerge from the underlying theory of strong interactions, quantum chromodynamics (QCD), is desired. The strongly interacting quarks and gluons at low energies are responsible for all the dynamics of nucleons and their clusters, the nuclei. The theoretical framework and the combination of analytical and numerical tools used to carry out a rigorous non-perturbative study of these systems from QCD is called lattice QCD. The result of a lattice QCD calculation corresponds to that of nature only in the limit when the volume of the spacetime is taken to infinity and the spacing between discretized points on the lattice is taken to zero. A better understanding of these discretization and volume effects, not only provides the connection to the infinite-volume continuum observables, but also leads to optimized calculations that can be performed with available computational resources. This thesis includes various formal developments in this direction, along with proposals for novel improvements, to be used in the upcoming LQCD studies of nuclear and hadronic systems. As the space(time) is discretized on a (hyper)cubic lattice in (most of) lattice QCD calculations, the lattice correlation functions are not fully rotationally invariant. This is known to lead to mixing between operators (those interpolating the states or inserting external currents) of higher dimensions with those of lower dimensions where the coefficients of latter diverge with powers of inverse lattice spacing, a, as the continuum limit is approached. This issue has long posed computational challenges in lattice spectroscopy of higher spin states, as well as in the lattice extractions of higher moments of hadron structure functions. We have shown, through analytical perturbative investigations of field theories, including QCD, on the lattice that a novel choice of operators, smeared over several lattice sites and deduced from a continuum angular momentum, has a smooth continuum limit. The scaling of the lower dimensional operators is proven to be no worse than a squared, explaining the success of recent numerical studies of excited state spectroscopy of hadrons with similar choices of operators. These results are presented in chapter 2 of this thesis. Due to Euclidean nature of lattice correlation function, the physical scattering parameters must be obtained via an analytical continuation to Minkowski spacetime. However, this continuation is practically impossible in the infinite-volume limit of lattice correlation function except at the kinematic thresholds. A formalism due to Luscher overcomes this issue by making the connection between the finite-volume spectrum of two interacting particles and their infinite-volume scattering phase shifts. We have extended the Luscher methodology, using an effective field theory approach, to the two-nucleon systems with arbitrary spin, parity and total momentum (in the limit of exact isospin symmetry) and have studied its application to the deuteron system, the lightest bound states of the nucleons, by careful analysis of the finite-volume symmetries. A proposal is presented that enables future precision lattice QCD extraction of the small D/S ratio of the deuteron that is known to be due to the action of non-central forces. By investigating another scenario, we show how significant volume improvement can be achieved in the masses of nucleons and in the binding energy of the deuteron with certain choices of boundary conditions in a lattice QCD calculation of these quantities. These results are discussed in chapters 3, 4 and 5. In order to account for electromagnetic effects in hadronic systems, lattice QCD calculations have started to include quantum electrodynamic (QED). These effects are particularly interesting in studies of mass splittings between charged and neutral members of isospin multiplets, e.g. neutral and charged pions. Due to the infinite range of QED interactions large volume effects plaque these studies. Using a non-relativistic effective theory for electromagnetic interactions of hadrons, we analytically calculate, and numerically estimate, the first few finite-volume corrections (up to 1 over L to the 4th power where L is the spatial extent of the volume) to the masses of hadrons and nuclei at leading order in the QED coupling constant, but to all orders in the short-distance strong interaction effects. These results are presented in chapter 6.
Download or read book Distinguishing Exotic States from Scattering States in Lattice QCD written by Dmitry Sigaev and published by . This book was released on 2008 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work explores the problem of distinguishing potentially interesting new exotic states in QCD from conventional scattering states using lattice QCD, and addresses the specific case of the search for localized resonances in a system of five quarks. We employ a complete basis of local interpolating operators, as well as a number of spatially distributed operators, to search for localized resonances in the system of five quarks. Motivated by initially promising experimental searches for the 8+(1540) pentaquark, we have set out to implement new approaches, both on the theoretical and computational side, to allow for calculations deemed infeasible by other groups searching for pentaquarks on the lattice. We restrict our system of five quarks to the quantum numbers of the O+(1540) pentaquark and get an insight into the structure of its states, calculate their energies and explore their properties. Finally, we use the obtained results to discriminate between scattering and exotic states. The calculation is performed in the quenched approximation with heavy Wilson fermions.
Download or read book Lattice Hadron Physics written by Alex Kalloniatis and published by Springer Science & Business Media. This book was released on 2005-05-20 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lattice Hadron Physics draws upon the developments made in recent years in implementing chirality on the lattice via the overlap formalism. These developments exploit chiral effective field theory in order to extrapolate lattice results to physical quark masses, new forms of improving operators to remove lattice artefacts, analytical studies of finite-volume effects in hadronic observables, and state-of-the-art lattice calculations of excited resonances. This volume, comprised of selected lectures, is designed to assist those outside the field who want quickly to become literate in these topics. As such, it provides graduate students and experienced researchers in other areas of hadronic physics with the background through which they can appreciate, if not become active in, contemporary lattice-gauge theory and its applications to hadronic phenomena.
Download or read book Lattice QCD at the Physical Point written by Thibaut Métivet and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book The Long Lasting Quest for Nuclear Interactions The Past the Present and the Future written by Laura Elisa Marcucci and published by Frontiers Media SA. This book was released on 2021-01-05 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The IVth International Conference on Quarks and Nuclear Physics written by Antonio Dobado and published by Springer Science & Business Media. This book was released on 2008-11-07 with total page 615 pages. Available in PDF, EPUB and Kindle. Book excerpt: The QNP series of international conferences on Quarks and Nuclear Physics is by now a well established and highly respected forum where the most recent developments in the field are discussed and communicated. QNP 2006 is the forth edition of this biennial meeting. Selected and refereed original contributions of QNP 2006 have been published in The European Physical Journal A - Hadrons and Nuclei (EPJ A), while the present proceedings book, in addition to reprinting the articles published in EPJ A, further includes all other contributions selected and accepted by the organizing committee for publication and archiving.
Download or read book Quarks Symmetries And Strings A Symposium In Honor Of Bunji Sakita s 60th Birthday written by Michio Kaku and published by World Scientific. This book was released on 1991-04-30 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quarks, Symmetries and Strings is a book that reflects the rich diversity of current research in physics: it describes quantum chromodynamics, quark phenomenology, superstring theory, supersymmetry, matrix models, statistical methods, superconductivity and neural networks. The book also reflects the diversity of Dr Bunji Sakita's scientific work. Dr Sakita has made seminal contributions in many of these areas. The book celebrates the many path-breaking ideas he pioneered which still cross-fertilize many of the most active areas of current research.
Download or read book Lattice written by and published by . This book was released on 1993 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt:
