Electromagnetic form factors of the pion and kaon from the instanton vacuum

Abstract

We investigate the pion and kaon (pi^+, K^+, K^0) electromagnetic form factors in the space-like region: Q^2 ~< 1 GeV, based on the gauged low-energy effective chiral action from the instanton vacuum in the large N_c limit. Explicit flavor SU(3) symmetry breaking is taken into account. The nonlocal contributions turn out to be crucial to reproduce the experimental data. While the pion electromagnetic form factor is in good agreement with the data, the kaon one seems underestimated. We also calculate the electromagnetic charge radii for the pion and kaon: <r^2>_{pi^+}=0.455 fm^2, <r^2>_{K^+}=0.486 fm^2 and <r^2>_{K^0}=-0.055 fm^2 without any adjustable free parameter except for the average instanton size and inter-instanton distance, and they are compatible with the experimental data. The low-energy constant L_9 in the large N_c limit is estimated to be 8.42*10^{-3} from the pion charge radius.

arXiv comment11 pages, 5 figures, submitted to PRD

References in corpus (38)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Instantons in QCD
• Instantons at work
• Measurement of the Charged Pion Electromagnetic Form Factor
• Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2
• The $\pi$, $K^{+}$, and $K^0$ electromagnetic form factors
• Evidence for the Role of Instantons in Hadron Structure from Lattice QCD
• Determination of the pion charge form factor for Q^2=0.60-1.60 GeV^2
• The Quark-Photon Vertex and the Pion Charge Radius
• Pion and Kaon Electromagnetic Form Factors
• Electromagnetic Pion Form Factor and Neutral Pion Decay Width
• A measurement of the axial form factor of the nucleon by the p(e,e'pi+)n reaction at W=1125 MeV
• Meson properties in an extended nonlocal NJL model
• Analytic coupling and Sudakov effects in exclusive processes: pion and ${\gamma }^{\ast }\gamma \to {\pi }^0$ form factors
• Instantons, the QCD Vacuum, and Hadronic Physics
• The pion form factor from lattice QCD with two dynamical flavours
• Lattice Computations of the Pion Form Factor
• Pion form factors with improved infrared factorization
• Short distance current correlators: Comparing lattice simulations to the instanton liquid
• Evidence for Instanton-Induced Dynamics, from Lattice QCD
• Adler function and hadronic contribution to the muon g-2 in a nonlocal chiral quark model
• Infrared and ultraviolet properties of the Landau gauge quark propagator
• Low energy constants of \chiPT from the instanton vacuum model
• Magnetic susceptibility of the QCD vacuum
• Leading-twist pion and kaon distribution amplitudes in the gauge-invariant nonlocal chiral quark model from the instanton vacuum
• Current mass dependence of the quark condensate and the constituent quark mass
• Instanton Contribution to the Pion Electro-Magnetic Formfactor at Q^2 > 1 GeV^2
• The Electromagnetic Pion Form Factor and Instantons
• 1/N_c corrections to the magnetic susceptibility of the QCD vacuum
• Pion radii in nonlocal chiral quark model
• A test of the instanton vacuum with low-energy theorems of the axial anomaly
• Exploring the Chiral Regime of QCD in the Interacting Instanton Liquid Model
• QCD condensates with flavor SU(3) symmetry breaking from the instanton vacuum
• Pion form factor in the Kroll-Lee-Zumino model
• Kaon semileptonic decay (K_{l3}) form factors from the instanton vacuum
• A lattice calculation of the pion form factor with Ginsparg-Wilson-type fermions
• A relation between the charge radii of π^{+},\K^{+},K^{o} derived by the general QCD parametrization

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• Electroweak properties of pions in a nuclear medium
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• Stability of the pion and the pattern of chiral symmetry breaking
• Pion electromagnetic form factor, perturbative QCD, and large-Nc Regge models
• Valence-quark distributions of pions and kaons in a nuclear medium
• Fragmentation functions and parton distribution functions for the pion with the nonlocal interactions
• Fragmentation and quark distribution functions for the pion and kaon with explicit flavor-SU(3)-symmetry breaking
• Pions valence quark distributions in asymmetric nuclear matter at finite temperature
• Pion weak decay constant at finite density from the instanton vacuum
• QCD magnetic susceptibility at finite temperature beyond the chiral limit
• Generalized form factors and spin structures of the kaon
• The quark-jet contribution to the fragmentation functions for the pion and kaon with the nonlocal interactions
• Vector and Axial-vector form factors in radiative kaon decay and flavor SU(3) symmetry breaking
• Electroweak properties of kaons in a nuclear medium
• Pion radiative weak decay from the instanton vacuum
• Heavy baryon production with an instanton interaction
• Heavy pseudoscalar-meson decay constants with strangeness from the extended nonlocal chiral-quark model
• Unpolarized fragmentation function for the pion and kaon via the nonlocal chiral-quark model
• Pion and kaon structures from the instanton vacuum
• QCD topological susceptibility from the nonlocal chiral quark model
• Heavy-light quark systems from the QCD instanton vacuum: $N_f=1$ light flavor case