Author: Harleen Dahiya
Publisher: LAP Lambert Academic Publishing
ISBN: 9783843362719
Category :
Languages : en
Pages : 140

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Book Description
Quantum Chromodynamics (QCD) views hadrons as bound states of quarks and gluons. However, hadron structure studies involve non-perturbative aspects of QCD- confinement and chiral symmetry breaking which makes it a challenging task to understand. Considerable progress has been achieved through Non- Relativistic Quark Model which is based on very simple assumptions and gives a remarkable fit to many of the hadron spectroscopy data. However, starting with the observations in 1988 by the European Muon Collaboration, in the last decade or so extremely important information pertaining to spin and flavor structure of the proton have been discovered in the deep inelastic scattering experiments. The present experimental information is in contradiction with the predictions of Non- Relativistic Quark Model which referred to as "proton spin problem". The chiral constituent quark model probes the regime between the confinement scale and the chiral symmetry breaking scale. Several current experimental initiatives in this direction indicate the importance of the problem for high energy physics community.

Author: Atsushi Hosaka
Publisher: World Scientific
ISBN: 9810246293
Category : Science
Languages : en
Pages : 389

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Book Description
This book describes baryon models constructed from quarks, mesons and chiral symmetry. The role of chiral symmetry and of quark model structure with SU(6) spin-flavor symmetry are discussed in detail, starting from a pedagogic introduction. Emphasis is placed on symmetry aspects of the theories. As an application, the chiral bag model is studied for nucleon structure, where important methods of theoretical physics, mostly related to the semiclassical approach for a system of strong interactions, are demonstrated. The text is more practical than formal; tools and ideas are explained in detail while solving actual problems. By checking each step of the computations, readers can learn not only the calculational techniques but also the essential ideas behind them.

Author: Georges Ripka
Publisher: Oxford University Press
ISBN: 9780198517849
Category : Science
Languages : en
Pages : 226

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Book Description
The structure of light hadrons is dominated by the spontaneously broken chiral symmetry of the strongly interacting (QCD) vacuum. Low energy properties of light hadrons can be described in terms of quarks interacting with chiral fields. This book gives a comprehensive account of a large class of models which describe the restoration of chiral symmetry at high temperature and density, the effective interactions between quarks, mesons as solutions of the Beth-Salpeter equation, and baryons in terms of solitions which rotate in flavor space. An in-depth analysis of regularization is given, including regularization by delocalized fields. Symmetry conserving approximations are formulated using both path integral and Feynmann graph methods. The book's style is pedagogical and well-suited to graduate and Ph.D. students who want to learn the techniques used in present day research. It can also serve as a reference for research and lecture courses.

Author: Reinhard Alkofer
Publisher: Springer Science & Business Media
ISBN: 3540494545
Category : Science
Languages : en
Pages : 126

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Book Description
These notes give an introduction to the description of hadrons, i.e., mesons and baryons, within a quark model based on a chirally invariant quantum field theory. Emphasis is put on a didactic approach intended for graduate students with some background on functional integral techniques. Starting from QCD a motivation of a specific form of the effective quark interaction is given. Functional integral bosonization leads to a theory describing successfully meson properties. It possesses solitonic solutions which are identified as baryons. Via functional integral techniques a Faddeev equation for baryons describing them as bound states of a diquark and a quark is derived. Finally, a unification of these two complementary pictures of baryons is proposed.

Author: Dmitri Diakonov
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
There is a prejudice that the chiral soliton model of baryons is something orthogonal to the good old constituent quark models. In fact, it is the opposite: the spontaneous chiral symmetry breaking in strong interactions explains the appearance of massive constituent quarks of small size thus justifying the constituent quark models, in the first place. Chiral symmetry ensures that constituent quarks interact very strongly with the pseudoscalar fields. The ''chiral soliton'' is another word for the chiral field binding constituent quarks. We show how the old SU(6) quark wave functions follow from the ''soliton'', however, with computable relativistic corrections and additional quark-antiquark pairs. We also find the 5-quark wave function of the exotic baryon Theta+.

Author: Universitat de València. Facultat de Física
Publisher:
ISBN:
Category :
Languages : en
Pages : 208

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Book Description

Author: Maciej A Nowak
Publisher: World Scientific
ISBN: 9814505501
Category : Science
Languages : en
Pages : 560

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Book Description
The physics of strongly interacting many-body systems known as nuclear physics is a mature discipline which has achieved a remarkably quantitative success. It has explained with an impressive accuracy the properties of nuclei from the deuteron to heavy nuclei containing several hundreds of nucleons. This is the more remarkable when one realizes that in no way did the success depend on the existence of, or knowledge derived from, the fundamental theory of strong interactions now believed to be quantum chromodynamics (QCD).This monograph is a first, albeit embryonic, attempt to explain how a nucleus can be understood without invoking the explicit degrees of freedom of quarks and gluons while still staying within the basic premise of QCD and furthermore why do quark-gluon signatures not show up prominently in nuclear processes, including those processes involving short-distance encounters within nuclei. Such an understanding is largely based on the modern concepts of broken chiral symmetry and is believed to be essential in uncovering new physics expected to figure in the hadronic environment under extreme conditions of high temperature and/or high density.

Author: Harald Fritzsch
Publisher: World Scientific
ISBN: 9814618128
Category : Science
Languages : en
Pages : 517

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Book Description
'Harald Fritzsch and Murray Gell-Mann, the two fathers of quantum chromodynamics, look back at the events that led to the discovery, and eventually acceptance, of quarks as constituent particles ... it is always worthwhile to reminisce about those times when theoretical physicists were truly eclectic, these stories are the testimony of a very active era, in which theoretical and experimental discoveries rapidly chased one another ... Of central importance now is the understanding of the composition of our universe, the dark matter and dark energy, the hierarchy of masses and forces, and a consistent quantum framework of unification of all forces of nature, including gravity. The closing contributions of the book put this venture in the context of today's high-energy physics programme, and make a connection to the most popular ideas in high-energy physics today, including supersymmetry, unification and string theory.'CERN CourierToday it is known that the atomic nuclei are composed of smaller constituents, the quarks. A quark is always bound with two other quarks, forming a baryon or with an antiquark, forming a meson. The quark model was first postulated in 1964 by Murray Gell-Mann — who coined the name “quark” from James Joyce's novel Finnegans Wake — and by George Zweig, who then worked at CERN. In the present theory of strong interactions — Quantum Chromodynamics proposed by H Fritzsch and Gell-Mann in 1972 — the forces that bind the quarks together are due to the exchange of eight gluons.On the 50th anniversary of the quark model, this invaluable volume looks back at the developments and achievements in the elementary particle physics that eventuated from that beautiful model. Written by an international team of distinguished physicists, each of whom have made major developments in the field, the volume provides an essential overview of the present state to the academics and researchers.

Author: Dieter Flamm
Publisher: Gordon & Breach Publishing Group
ISBN:
Category : Science
Languages : en
Pages : 478

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Book Description
Band 1.

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

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Book Description
A covariant quark model, based both on the spectator formalism and on Vector Meson Dominance, and previously calibrated by the physical data, is here extended to the unphysical region of the lattice data by means of one single extra adjustable parameter - the constituent quark mass in the chiral limit. We calculated the Nucleon (N) and the Gamma N -> Delta form factors in the universe of values for that parameter described by quenched lattice QCD. A qualitative description of the Nucleon and Gamma N -> Delta form factors lattice data is achieved for light pion masses.