Weak magnetic field corrections to light vector or axial mesons mixings and vector meson dominance

Braghin, Fábio L.

doi:10.1088/1361-6471/aba7c9

Cited by 8 publications

(5 citation statements)

References 58 publications

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“…By considering the quark propagator with the electromagnetic quark coupling, the relations (3) are preserved. This gauge invariance has the same roots of the description in terms of the auxiliary fields to describe electromagnetic couplings of charged mesons and their resulting couplings with (background) constituent quarks analyzed in [44,[50][51][52]. In the limit of degenerate quark effective masses, M u = M d = M s , the coupling constants reduce to a single constant that, as discussed below, will be normalized to be the coupling constant of reference G 0 such that G i j → G 0 δ i j , and the standard treatment of the model can be done.…”

Section: Masses and Coupling Constants: A Self-consistent Analysismentioning

confidence: 94%

Strangeness content of the pion in the U(3) Nambu–Jona–Lasinio model

Braghin¹

2022

J. Phys. G: Nucl. Part. Phys.

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The Nambu-Jona-Lasinio model is considered with flavor-dependent coupling constants $G_{ij} \left[ ( \bar{\psi} \lambda_i \psi ) ( \bar{\psi} \lambda_j \psi ) + ( \bar{\psi} i\gamma_5 \lambda_i \psi ) ( \bar{\psi} i \gamma_5\lambda_j \psi ) \right]$ for $i,j=0,1..N_f^2-1$, and $N_f=3$. A self consistent calculation of quark effective masses and coupling constants is performed making the strange quark effective mass to vary considerably. Quantum mechanical mixings between up, down and strange constituent quarks yields a strangeness content of the light u and d quarks constituent and of the pion. Different types of estimates for the strangeness contribution for the pion mass are provided. Mixing type interactions, $G_{i\neq j}$, induce the light mesons mixings and estimates for the $\pi^0-\eta$ and $\eta-\eta'$ mixings are provided. The $\eta-\pi^0$ mixing is argued to be an indication of the strangeness content of the pion.

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Section: Masses and Coupling Constants: A Self-consistent Analysismentioning

confidence: 94%

Strangeness content of the pion in the U(3) Nambu–Jona–Lasinio model

Braghin¹

2022

J. Phys. G: Nucl. Part. Phys.

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“…Field renormalization constants were introduced explicitly in Refs. [22,23]. Bilocal auxiliary fields for the different flavors can be expanded in an infinite orthogonal basis with all the excitations in the corresponding channel [8].…”

Section: The Quark Determinant Light Mesons and Constituent Quark Cur...mentioning

confidence: 99%

Light meson-quark couplings and radii: ratios from one loop calculation

Braghin¹

2022

Proceedings of XV International Workshop on Hadron Physics — PoS(XVHadronPhysics)

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In this work some results for light mesons couplings to constituent quarks obtained in a one loop calculation are compared among each other in the limit of large quark effective mass. These coupling constants are extracted from momentum dependent form factors obtained in a dynamical approach from an important term of the QCD quark-effective action. For this, exact and approximated ratios of the different light meson-constituent quark coupling constants are provided. The comparison is also done for the different light mesons and constituent quark averaged quadratic radii.

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“…Based on a quark loop mechanism of mixing, it was determined that the mixing amplitude significantly depends on momentum. Subsequently, the investigation of various loop mechanisms for mixing was initiated in different models, such as the global color model [13], extended Nambu-Jona-Lasinio (NJL) model [14,15], chiral constituent quark model [16,17], and hidden local symmetry model [18−20]. In our pervious study [21], we examined mixing using a model independent approach through Resonance Chiral Theory (RχT) [22].…”

Section: Introductionmentioning

confidence: 99%

Momentum dependence of mixing in the pion vector form factor and its effect on *

Chen,

Qin

2023

Chinese Phys. C

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The inclusion of the $\rho-\omega$ mixing effect is essential for a precisedescription of the pion electromagnetic form factor in the $e^+e^- \rightarrow\pi^+\pi^-$ process, which quantifies the two-pion contribution to the anomalous magnetic moment of themuon $a_\mu$. In this paper, we aim to analyse the impact of the momentum dependence of the $\rho-\omega$ mixing within the framework of resonance chiral theory. The momentum dependence of the $\rho-\omega$ mixingis incorporated by considering loop contributions at the next-to-leading order in the $1/N_C$ expansion. We revisit the work {[}Y. H. Chen, D. L. Yao, and H. Q. Zheng,Commun. Theor. Phys. 69 (2018) 1{]}, considering the contribution arising from the kaon mass splitting in the kaon loops and the latest experimental data.We perform two kinds of fits (with momentum-independent or momentum-dependent $\rho-\omega$ mixing amplitude) to describe the $e^+e^-\rightarrow \pi^+\pi^-$and $\tau\rightarrow \nu_{\tau}2\pi$ data within the energy region of 600$\sim$900 MeV and the decay width of $\omega \rightarrow \pi^+\pi^-$, and compare their results.Our findings indicate that both the momentum-independent and momentum-dependent $\rho-\omega$ mixing schemes provide appropriate descriptions of the data. However, the momentum-dependent scheme exhibits greater self-consistency, considering the reasonable imaginary part of the mixing matrix element $\Pi_{\rho\omega}$ obtained.Regarding the contribution to the anomalous magnetic moment of the muon, $a_\mu^{\pi\pi}|_{[0.6,0.9]\text{GeV}}$, the results obtained from the fits considering the momentum-dependent $\rho-\omega$ mixing amplitude agree well with those obtained without incorporating the momentum dependence of the $\rho-\omega$ mixing, within the margin of errors.Furthermore, based on the fitted values of the relevant parameters, we observe that the decay width of $\omega \rightarrow \pi^+\pi^-$ is predominantly influenced by the $\rho-\omega$ mixing effect. Additionally, we find that including the direct $\omega_I\rightarrow \pi^+\pi^-$ coupling is crucial in the analysis for extracting the mass of the $\omega$ meson from the $e^+e^- \rightarrow\pi^+\pi^-$ process. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd

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Weak magnetic field corrections to light vector or axial mesons mixings and vector meson dominance

Abstract: Weak magnetic-field-induced corrections to effective coupling constants describing light vector meson mixing and vector meson dominance (VMD) are derived. The magnetic field must be weak with respect to an effective quark mass M* such that: Show more

Cited by 8 publications

References 58 publications

Strangeness content of the pion in the U(3) Nambu–Jona–Lasinio model

Strangeness content of the pion in the U(3) Nambu–Jona–Lasinio model

Light meson-quark couplings and radii: ratios from one loop calculation

Momentum dependence of mixing in the pion vector form factor and its effect on *

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