[PDF] Chiral Perturbation Theory With Nucleons eBook

Author :
Publisher :
Page : 40 pages
File Size : 48,35 MB
Release : 1991
Category :
ISBN :

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I review the constraints posed on the interactions of pions, nucleons and photons by the spontaneously broken chiral symmetry of QCD. The framework to perform these calculations, chiral perturbation theory, is briefly discussed in the meson sector. The method is a simultaneous expansion of the Greens functions in powers of external moments and quark masses around the massless case, the chiral limit. To perform this expansion, use is made of a phenomenological Lagrangian which encodes the Ward-identities and pertinent symmetries of QCD. The concept of chiral power counting is introduced. The main part of the lectures of consists in describing how to include baryons (nucleons) and how the chiral structure is modified by the fact that the nucleon mass in the chiral limit does not vanish. Particular emphasis is put on working out applications to show the strengths and limitations of the methods. Some processes which are discussed are threshold photopion production, low-energy compton scattering off nucleons,?N scattering and the?-term. The implications of the broken chiral symmetry on the nuclear forces are briefly described. An alternative approach, in which the baryons are treated as very heavy fields, is touched upon.

Author : Maciej A Nowak
Publisher : World Scientific
Page : 560 pages
File Size : 33,80 MB
Release : 1996-09-03
Category : Science
ISBN : 9814505501

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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 : Stefan Scherer
Publisher : Springer Science & Business Media
Page : 346 pages
File Size : 49,35 MB
Release : 2011-10-02
Category : Science
ISBN : 364219253X

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Chiral Perturbation Theory, as effective field theory, is a commonly accepted and well established working tool, approximating quantum chromodynamics at energies well below typical hadron masses. This volume, based on a number of lectures and supplemented with additional material, provides a pedagogical introduction for graduate students and newcomers entering the field from related areas of nuclear and particle physics. Starting with the the Lagrangian of the strong interactions and general symmetry principles, the basic concepts of Chiral Perturbation Theory in the mesonic and baryonic sectors are developed. The application of these concepts is then illustrated with a number of examples. A large number of exercises (81, with complete solutions) are included to familiarize the reader with helpful calculational techniques.