35 research outputs found
Effective Chiral Meson Lagrangian For The Extended Nambu-Jona-Lasinio Model
We present a derivation of the low-energy effective meson Lagrangian of the
extended Nambu -- Jona-Lasinio (ENJL) model. The case with linear realization
of broken chiral symmetry is considered. There are two
crucial points why this revision is needed. Firstly it is the explicit chiral
symmetry breaking effect. On the basis of symmetry arguments we show that
relevant contributions related with the current quark mass terms are absent
from the effective Lagrangians derived so far in the literature. Secondly we
suggest a chiral covariant way to avoid non-diagonal terms responsible for the
pseudoscalar -- axial-vector mixing from the effective meson Lagrangian. In the
framework of the linear approach this diagonalization has not been done
correctly. We discuss as well the coset space
parametrization for the revised Lagrangian (nonlinear ansatz). Our Lagrangian
differs in an essential way from those that have been derived till now on the
basis of both linear and nonlinear realizations of chiral symmetry.Comment: 23 pages, plain LaTex, no figure
Baryons as non-topological chiral solitons
The present review gives a survey of recent developments and applications of
the Nambu--Jona-Lasinio model with and quark flavors for the
structure of baryons. The model is an effective chiral quark theory which
incorporates the SU(N)SU(N)U(1) approximate
symmetry of Quantum chromodynamics. The approach describes the spontaneous
chiral symmetry breaking and dynamical quark mass generation. Mesons appear as
quark-antiquark excitations and baryons arise as non-topological solitons with
three valence quarks and a polarized Dirac sea. For the evaluation of the
baryon properties the present review concentrates on the non-linear
Nambu--Jona-Lasinio model with quark and Goldstone degrees of freedom which is
identical to the Chiral quark soliton model obtained from the instanton liquid
model of the QCD vacuum. In this non-linear model, a wide variety of
observables of baryons of the octet and decuplet is considered. These include,
in particular, electromagnetic, axial, pseudoscalar and pion nucleon form
factors and the related static properties like magnetic moments, radii and
coupling constants of the nucleon as well as the mass splittings and
electromagnetic form factors of hyperons. Predictions are given for the strange
form factors, the scalar form factor and the tensor charge of the nucleon.Comment: 104 pages, 27 figures as uuencoded and compressed postscript files ,
hardcopy available upon request; Prog.Part.Nucl.Phys. 37 (1996) (in print
Bestimmung von Digoxin im Serum Vergleich von Radioimmunassay und heterogenem Enzymimmunassay
Personalmanagement und Dienstrechtsreform an deutschen Hochschulen — eine kritische Analyse
Arbeitsbericht 1971 der Zentralabteilung Strahlenschutz
The "Zentralabteilung Strahlenschutz - ZST" (Health Physics Division) of the Nuclear Research Establishment Jülich is responsible for an adequate and a proper performance of the radiation protection of installations, personnel and environment. This does include the introduction of the necessary organizing conditions as well as the permanent development of the measuring methods and procedures according to the most recent knowledge of science and research. The chapters 1 to 6 of the present annual report refer to the service activities done in 1971 as well as to the results of investigations and developments in connection with the improvement of methods and procedures. Chapter 7 gives a complete bibliography of all the published and internal literature of the ZST in 1971