Mixing Angle of Scalar Mesons and Kaon Polarizability in a Chiral Quark σ-Model

1997 ◽  
Vol 12 (24) ◽  
pp. 4399-4409 ◽  
Author(s):  
D. Ebert ◽  
M. K. Volkov ◽  
T. Feldmann
Keyword(s):  
Chiral Symmetry ◽  
Symmetry Limit ◽  
Mixing Angle ◽  
Scalar Mesons ◽  
Neutral Kaons

Using present data for the decays f0 → γγ, f0 → ππ, we determine the mixing angle of scalar mesons in a chiral quark σ-model. This value is employed for an analysis of the kaon polarizability. It is shown that pole diagrams from intermediate scalar mesons and their mixing angle significantly affect the electromagnetic polarizability of charged and neutral kaons. Our results are compared to other models and the results of the chiral symmetry limit.

ISOVECTOR COMPONENTS OF THE SCALAR σ-MESON FAMILY AS NEW INGREDIENTS FOR NUCLEAR MATTER MODELS

2007 ◽  
Vol 16 (02n03) ◽  
pp. 325-332 ◽  
Author(s):  
EDUARDO LÜTZ ◽  
MOISÉS RAZEIRA ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
BARDO E. J. BODMANN ◽  
FERNANDO PILOTTO
Keyword(s):  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Chiral Symmetry ◽  
Symmetry Transformation ◽  
Recent Analysis ◽  
Scalar Mesons ◽  
The Family ◽  
Macroscopic Properties ◽  
Light Scalar

On the basis of a chiral symmetry transformation, we predict an isovector component for the family of light scalar mesons, i.e. partners of the σ-meson. Such a contribution may be necessary to tune the equation of state of nuclear matter in order to comply with severe constraints from a recent analysis of observational macroscopic properties of neutron stars.

Nonrenormalization Theorem in the Chiral Symmetry Limit

1973 ◽  
Vol 30 (13) ◽  
pp. 630-633 ◽  
Author(s):  
Paul Langacker ◽  
Heinz Pagels
Keyword(s):  
Chiral Symmetry ◽  
Symmetry Limit

scholarly journals Inverse mass hierarchy of light scalar mesons driven by anomaly-induced flavor breaking

2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Yoshiki Kuroda ◽  
Masayasu Harada ◽  
Shinya Matsuzaki ◽  
Daisuke Jido
Keyword(s):  
Symmetry Breaking ◽  
Chiral Symmetry ◽  
Scalar Meson ◽  
Chiral Symmetry Breaking ◽  
Linear Sigma Model ◽  
Mass Hierarchy ◽  
Scalar Mesons ◽  
Light Scalar ◽  
Symmetry Breaking Term ◽  
Breaking Term

Abstract We propose a novel mechanism to reproduce the observed mass hierarchy for scalar mesons lighter than 1 GeV (called the inverse hierarchy), regarding them as mesons made of a quark and an anti-quark ($q\bar{q}$ mesons). The source is provided by the SU(3) flavor-symmetry breaking induced by the U(1) axial anomaly. In particular, the anomaly term including the explicit chiral symmetry breaking plays a significant role in the light scalar meson spectrum. To be concrete, we construct a linear sigma model for scalar mesons of $q\bar{q}$ type together with their pseudoscalar chiral partners, including an anomaly-induced explicit chiral symmetry-breaking term. We find that, due to the proposed mechanism, the inverse hierarchy, i.e., $m\left[ a_0 (980) \right] \simeq m\left[ f_0 (980) \right] > m \left[ K_0^\ast (700) \right] > m \left[ f_0(500) \right]$, is indeed realized. Consequently, the quark content of $f_0 (500)$ is dominated by the isoscalar $\bar uu+ \bar dd$ component, and $f_0 (980)$ by the strange quark bilinear one, $s\bar{s}$.

scholarly journals Connections between chiral Lagrangians and QCD sum-rules

2016 ◽  
Vol 31 (03) ◽  
pp. 1650023 ◽  
Author(s):  
Amir H. Fariborz ◽  
A. Pokraka ◽  
T. G. Steele
Keyword(s):  
Chiral Lagrangians ◽  
Sum Rules ◽  
Chiral Symmetry Breaking ◽  
Vacuum Expectation ◽  
Qcd Sum Rules ◽  
Mixing Angle ◽  
Scalar Mesons ◽  
Scale Factors ◽  
Quark Level ◽  
Light Scalar

In this paper, it is shown how a chiral Lagrangian framework can be used to derive relationships connecting quark-level QCD correlation functions to mesonic-level two-point functions. Crucial ingredients of this connection are scale factor matrices relating each distinct quark-level substructure (e.g. quark–antiquark, four-quark) to its mesonic counterpart. The scale factors and mixing angles are combined into a projection matrix to obtain the physical (hadronic) projection of the QCD correlation function matrix. Such relationships provide a powerful bridge between chiral Lagrangians and QCD sum-rules that are particularly effective in studies of the substructure of light scalar mesons with multiple complicated resonance shapes and substantial underlying mixings. The validity of these connections is demonstrated for the example of the isotriplet [Formula: see text] system, resulting in an unambiguous determination of the scale factors from the combined inputs of QCD sum-rules and chiral Lagrangians. These scale factors lead to a remarkable agreement between the quark condensates in QCD and the mesonic vacuum expectation values that induce spontaneous chiral symmetry breaking in chiral Lagrangians. This concrete example shows a clear sensitivity to the underlying [Formula: see text]-system mixing angle, illustrating the value of this methodology in extensions to more complicated mesonic systems.

scholarly journals Universal scale factors relating mesonic fields and quark operators

2020 ◽  
Vol 35 (21) ◽  
pp. 2050173
Author(s):  
Amir H. Fariborz ◽  
J. Ho ◽  
T. G. Steele
Keyword(s):  
Chiral Symmetry ◽  
Chiral Lagrangians ◽  
Sum Rules ◽  
Scale Factor ◽  
Low Energy ◽  
Qcd Sum Rules ◽  
Scalar Mesons ◽  
Scale Factors ◽  
Quark Level ◽  
Universal Scale

Scale factor matrices relating mesonic fields in chiral Lagrangians and quark-level operators of QCD sum-rules are shown to be constrained by chiral symmetry, resulting in universal scale factors for each chiral nonet. Built upon this interplay between chiral Lagrangians and QCD sum-rules, the scale factors relating the [Formula: see text] isotriplet scalar mesons to their underlying composite quark fields were recently determined. It is shown that the same technique when applied to [Formula: see text] isodoublet scalars reproduces the same scale factors, confirming the universality property and further validating this connection between chiral Lagrangians and QCD sum-rules, which can have nontrivial impacts on our understanding of the low-energy QCD, in general, and the physics of scalar mesons in particular.

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