Journal ArticleDOI
Spectral function sum rules and the SU(3) violation of quark condensates in quantum chromodynamics
S Debnath,B Bagchi +1 more
TLDR
In this paper, the pseudoscalar densities were used to obtain bounds on the quark vacuum condensate ratio (ss)/(uu) for the U(1) sector.Abstract:
Positivity conditions on the spectral representation of the pseudoscalar densities are used to obtain bounds on the quark vacuum condensate ratio (ss)/(uu). These relate (ss)/(uu) to the topological susceptibility G(0) of the U(1) sector and appear to favour a smaller value for this quantity than is given by the current-algebra result.read more
Citations
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Journal ArticleDOI
Flavour symmetry breaking in quark vacuum condensates
TL;DR: In this article, the SU(3) and SU(2) flavour symmetry violations in the vacuum were studied from the viewpoint of nonperturbative quark mass generation and independently from charge symmetry-breaking considerations.
Journal ArticleDOI
Pion-nucleon σ-term : a QCD assessment
Shukla Basu,Subhra Niyogi +1 more
TL;DR: Using a QCD estimate on the quark-vacuum condensate ratio (ss)0/(uu)0, the authors showed that the ratio of the meson wavefunction renormalization constants ZK12/Zpi 1/2 may deviate considerably from the SU(3) symmetric value of unity.
References
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Flavor su(2) and su(3) symmetry breaking in quantum chromodynamics
C.A. Dominguez,M. Loewe +1 more
TL;DR: The light-quark mass differences are calculated in the framework of the Laplace-transform QCD sum rules using an improved parametrization of the hadronic spectral functions and imply a small flavor symmetry breaking in the QCD nonperturbative vacuum.
Journal ArticleDOI
The use of the finite-energy sum rules for the calculation ofγ=1−〈s-s〉/〈u/-u〉
N. V. Krasnikov,A. A. Pivovarov +1 more
TL;DR: In this article, the finite-energy sum rules are used for the estimate of the SU3 symmetry-breaking parameter γ = 0.43±0.12. But γ is not a constant.
Journal ArticleDOI
Solving the anomalous Ward identities for the U(1) problem
TL;DR: Anomalous Ward identities were obtained for spontaneously realized SU(3) x SU( 3) x U/sub 3/(1) in the presence of realistic symmetry-breaking quark mass terms in the Lagrangian.
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The pseudoscalar mass spectrum as evidence for gluons, anomalies and topological charge
TL;DR: In this paper, the complete set of anomalous Ward identities for the spontaneous breaking of U(3) × U (3) applied to the pseudoscalar nonet spectrum is shown to provide evidence for gluons, gluon anomalies and non-trivial topological charge.
Journal ArticleDOI
Glueball candidate iota(1440), anomalous Ward identities, and two-photon decays
TL;DR: Anomalous Ward identities are given for the U(1) problem, showing that some recent papers have neglected the large topological susceptibility coming from the pure Yang-Mills sector of QCD as discussed by the authors.