Electromagnetic axial anomaly in a generalized linear sigma model

Within the framework of the generalized linear sigma model with glueballs recently proposed [1,2], we study the schematic spectroscopy of scalar and pseudoscalar mesons in the SU(3) flavor limit and explore their quark and glue contents. In this framework, for both scalars and pseudoscalars, the two octet physical states are admixtures of quark-antiquark and four-quark components, and the three singlet states contain quark-antiquark, four-quark and glue components. We identify the two scalar octets with a0(980) and a0(1450) and the two pseudoscalar octets with π(137) and π(1300). We show that, as expected, the light pseudoscalar octet is made dominantly of quark-antiquarks whereas the light scalar octet has a reversed substructure with a dominant four-quark component. The case of singlets is more complex due to surplus of states up to around 2 GeV. We consider all 35 permutations for identifying the three pseudoscalar singlets of our model with three of the seven experimental candidates. Our numerical simulation unambiguously identifies the lightest and the heaviest pseudoscalar singlets with η(547) and η(2225), respectively, and favors the identification of the middle singlet with either η(1295) or η(1405) [or, to a lesser extent, with η(1475)] and thereby allows a probe of their substructures. We then estimate the quark and glue components and find that the three pseudoscalar singlets (from lightest to heaviest) are mainly of quark-antiquark, fourquark and glue substructure, while the corresponding three scalar singlets (from lightest to heaviest) are of four-quark, quark antiquark and glue contents. The masses of pure pseudoscalar and scalar glueballs are estimated around 2.0 and 1.6 GeV, respectively.

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“…where γ 1 and γ 2 are arbitrary parameters that must satisfy the constraint: γ 1 + γ 2 = 1 [40]- [48]. The next term f S breaks scale symmetry…”

Section: Brief Review Of the Theoretical Frameworkmentioning

confidence: 99%

Quark and glue spectroscopy of scalars and pseudoscalars in SU(3) flavor limit

Fariborz

Jora

Lyukova

2019

Int. J. Mod. Phys. A

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“…An extra term corresponding to the electromagnetic axial anomaly was further introduced in [30], where the decays of the pseudoscalar mesons to two photons were computed and studied with good agreement with experimental data. It seems then natural to extend this picture to include also the trace anomaly and analyze the decays of scalar mesons to two photons in the same context.…”

Section: Introductionmentioning

confidence: 99%

“…In a series of papers [27][28][29][30][31][32] we proposed and studied in detail a generalized linear sigma model with two chiral nonets, one with a two quark substructure and the other one with a four-quark content. In this framework the physical scalar states were found to have a significant admixture of two-and four-quark components, with those below 1 GeV generally containing a larger four-quark component compared to those above 1 GeV.…”

Section: Introductionmentioning

confidence: 99%

“…The generalized linear sigma model described in [27][28][29][30][31][32] contained, in addition to the relevant terms pertaining to mass and interactions, a term that mocks up the gluon axial anomaly. An extra term corresponding to the electromagnetic axial anomaly was further introduced in [30], where the decays of the pseudoscalar mesons to two photons were computed and studied with good agreement with experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Electromagnetic trace anomaly in a generalized linear sigma model

Fariborz

Jora

2017

Phys. Rev. D

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We build the electromagnetic trace anomaly effective term for a generalized linear sigma model with two chiral nonets, one with a quark-antiquark structure and the other one with a four-quark content. In the leading order of this framework, we study the decays into two photons of the lowest isosinglet scalar mesons. We find that the direct inclusion of underlying mixing among two-and four-quark components in the trace anomaly term is essential in order for the model prediction to agree with the available experimental data on the decay width of f 0 ð980Þ to two photons. Consequently, this sets a lower bound of 0.5 KeVon the decay with of f 0 ð500Þ to two photons.

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“…The axial and trace anomalies in a linear sigma model refer both to the electromagnetic and the gluon fields. In [47,48] we studied the effect of the electromagnetic axial and trace anomalies on the decays to two photons of some of the scalar and pseudoscalar states. However the treatment of the gluon anomalies is somewhat different because the gauge invariant glueball states may behave as individual degrees of freedom which may be either integrated out from the Lagrangian or maintained as physical states.…”

Section: Introductionmentioning

confidence: 99%

Generalized linear sigma model with two glueballs

Fariborz

Jora

2018

Phys. Rev. D

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We present a generalized linear sigma model that includes both scalar and pseudoscalar glueballs in addition to a quark-antiquark as well as a four-quark chiral nonet. Utilizing the axial and trace anomalies of QCD (at the effective mesonic level), we aim to develope the most general structure of the Lagrangian which can be used to study the interaction of quarkonia with glueballs. We then study the effect of scalar glueball on the vacuum of the model by considering a decoupling limit in which the glueball fields are decoupled from quarkonia. This determines the properties of the pure scalar glueball and builds a practical foundation for determining the model parameters when the interactions are turned on.

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Electromagnetic axial anomaly in a generalized linear sigma model

Cited by 9 publications

References 49 publications

Quark and glue spectroscopy of scalars and pseudoscalars in SU(3) flavor limit

Quark and glue spectroscopy of scalars and pseudoscalars in SU(3) flavor limit

Electromagnetic trace anomaly in a generalized linear sigma model

Generalized linear sigma model with two glueballs

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