ON THE SIGNIFICANCE OF RECENT LATTICE RESULTS FOR THE CHIRAL LAGRANGIAN

2008 ◽  
Vol 23 (21) ◽  
pp. 3187-3190
Author(s):  
H. LEUTWYLER
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Quark Condensate ◽  
Low Energy ◽  
Coupling Constants ◽  
Chiral Perturbation ◽  
Decay Constants ◽  
Energy Domain ◽  
The Masses ◽  
Ozi Rule

The report concerns only one of the issues discussed in my talk at ICFP 2007: the significance of recent lattice results for our understanding of the nonperturbative phenomena in the low energy domain of QCD. All of these results are consistent with the phenomenological estimates for the coupling constants of the chiral SU (2)× SU (2) Lagrangian and thereby corroborate the predictions based on these. In the case of SU (3)× SU (3), the results also confirm the old estimates obtained from chiral perturbation theory. In particular, the first two terms in the expansion of the masses and decay constants in powers of ms appear to represent a decent approximation for the full series. Some of the lattice results indicate that the quark condensate violates the OZI-rule rather strongly, but as there are some discrepancies concerning this issue, it is too early to draw conclusions.

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 New method for fitting the low-energy constants in chiral perturbation theory

2020 ◽  
Vol 102 (9) ◽  
Author(s):  
Qin-He Yang ◽  
Wei Guo ◽  
Feng-Jun Ge ◽  
Bo Huang ◽  
Hao Liu ◽  
...  
Keyword(s):  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Low Energy ◽  
New Method ◽  
Chiral Perturbation ◽  
Energy Constants
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