scholarly journals Global Colour Model of QCD and Its Relationship to the NJL Model, Chiral Perturbation Theory and Other Models

1997 ◽  
Vol 50 (1) ◽  
pp. 103 ◽  
Author(s):  
Reginald T. Cahill ◽  
Susan M. Gunner
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Mass Formula ◽  
Gluon Propagator ◽  
Chiral Perturbation ◽  
Successful Model ◽  
Njl Model ◽  
New Form ◽  
The Difference ◽  
Bag Constant

The Global Colour Model (GCM) of QCD is a very successful model. Not only is it formally derivable from QCD but under various conditions it reduces to the NJL model and also to Chiral Perturbation Theory, and to other models. Results presented include the effective gluon propagator, the difference between constituent and exact quark propagators, various meson and nucleon observables, a new form for the mass formula for the Nambu–Goldstone mesons of QCD, and the change in the MIT bag constant in nuclei.

scholarly journals On the rotator Hamiltonian for the SU (N) × SU (N) sigma model in the delta regime

2020 ◽  
Vol 2020 (7) ◽  
Author(s):  
J Balog ◽  
F Niedermayer ◽  
P Weisz
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Sigma Model ◽  
Two Dimensions ◽  
Leading Order ◽  
Chiral Perturbation ◽  
Casimir Invariant ◽  
The Difference

Abstract We investigate some properties of the standard rotator approximation of the $\mathrm{SU}(N)\times\mathrm{SU}(N)$ sigma-model in the delta regime. In particular, we show that the isospin susceptibility calculated in this framework agrees with that computed by chiral perturbation theory up to next-to-next-to-leading order in the limit $\ell=L_t/L\to\infty$. The difference between the results involves terms vanishing like $1/\ell$, plus terms vanishing exponentially with $\ell$. As we have previously shown for the O($n$) model, this deviation can be described by a correction to the rotator spectrum proportional to the square of the quadratic Casimir invariant. Here we confront this expectation with analytic nonperturbative results on the spectrum in two dimensions for $N=3$.

scholarly journals The axion-baryon coupling in SU(3) heavy baryon chiral perturbation theory

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Thomas Vonk ◽  
Feng-Kun Guo ◽  
Ulf-G. Meißner
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Heavy Baryon ◽  
Power Counting ◽  
Flavor Symmetry ◽  
Chiral Perturbation ◽  
Third Order ◽  
Stellar Objects ◽  
The Past ◽  
Dense Nuclear Matter

Abstract In the past, the axion-nucleon coupling has been calculated in the framework of SU(2) heavy baryon chiral perturbation theory up to third order in the chiral power counting. Here, we extend these earlier studies to the case of heavy baryon chiral perturbation theory with SU(3) flavor symmetry and derive the axion coupling to the full SU(3) baryon octet, showing that the axion also significantly couples to hyperons. As studies on dense nuclear matter suggest the possible existence of hyperons in stellar objects such as neutron stars, our results should have phenomenological implications related to the so-called axion window.

Light front Hamiltonian for boson form of QED (1 + 1) in Pauli–Villars regularization

2019 ◽  
Vol 34 (21) ◽  
pp. 1950113
Author(s):  
V. A. Franke ◽  
M. Yu. Malyshev ◽  
S. A. Paston ◽  
E. V. Prokhvatilov ◽  
M. I. Vyazovsky
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Condensate ◽  
Light Front ◽  
Coupling Constants ◽  
Hamiltonian Approach ◽  
Chiral Perturbation ◽  
Dimensional Models ◽  
Villars Regularization ◽  
Ultraviolet Regularization

Light front (LF) Hamiltonian for QED in [Formula: see text] dimensions is constructed using the boson form of this model with additional Pauli–Villars-type ultraviolet regularization. Perturbation theory, generated by this LF Hamiltonian, is proved to be equivalent to usual covariant chiral perturbation theory. The obtained LF Hamiltonian depends explicitly on chiral condensate parameters which enter in a form of some renormalization of coupling constants. The obtained results can be useful when one attempts to apply LF Hamiltonian approach for [Formula: see text]-dimensional models like QCD.

scholarly journals K0 → π0γγ decays in chiral perturbation theory

1987 ◽  
Vol 189 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Gerhard Ecker ◽  
Antonio Pich ◽  
Eduardo De Rafael
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Perturbation

scholarly journals Unphysical phases in staggered chiral perturbation theory

2016 ◽  
Vol 93 (8) ◽  
Author(s):  
Christopher Aubin ◽  
Katrina Colletti ◽  
George Davila
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Chiral Perturbation
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