Accuracy of the pion elastic form factor extracted from a local-duality sum rule

Abstract

We analyze the accuracy of the pion elastic form factor predicted by a local-duality (LD) version of dispersive sum rules. To probe the precision of this theoretical approach, we adopt potential models with interactions that involve both Coulomb and confining terms. In this case, the exact form factor may be obtained from the solution of the Schroedinger equation and confronted with the LD sum rule results. We use parameter values appropriate for hadron physics and observe that, independently of the details of the confining interaction, the deviation of the LD form factor from the exact form factor culminates in the region Q^2~4-6 GeV^2. For larger Q^2, the accuracy of the LD description increases rather fast with Q^2. A similar picture is expected for QCD. For the pion form factor, existing data suggest that the LD limit may be reached already at the relatively low values Q^2=4-10 GeV^2. Thus, large deviations of the pion form factor from the behaviour predicted by LD QCD sum rules for higher values of Q^2, as found by some recent analyses, appear to us quite improbable. New accurate data on the pion form factor at Q^2=4-10 GeV^2 expected soon from JLab will have important implications for the behaviour of the pion form factor in a broad Q^2 range up to asymptotically large values of Q^2.

12 pages, extended version, conclusions remain unchanged

References in corpus (20)

• Light-Front Dynamics and AdS/QCD Correspondence: The Pion Form Factor in the Space- and Time-Like Regions
• Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2
• Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
• The effective continuum threshold in dispersive sum rules
• OPE, charm-quark mass, and decay constants of D and D_s mesons from QCD sum rules
• Systematic uncertainties of hadron parameters obtained with QCD sum rules
• Decay constants of heavy pseudoscalar mesons from QCD sum rules
• Pion in the Holographic Model with 5D Yang-Mills Fields
• Extraction of ground-state decay constant from dispersive sum rules: QCD vs potential models
• Can one control systematic errors of QCD sum rule predictions for bound states?
• Pion form factor at spacelike momentum transfers from local-duality QCD sum rule
• QCD sum rules with nonlocal condensates and the spacelike pion form factor
• Effective continuum threshold for vacuum-to-bound-state correlators
• Dispersion representations and anomalous singularities of the triangle diagram
• Bound-state parameters from dispersive sum rules for vacuum-to-vacuum correlators
• Extraction of bound-state parameters from dispersive sum rules
• Quark-hadron duality and hadron properties from correlators of pseudoscalar and axial currents
• Rigorous pion electromagnetic form factor behavior in the space-like region
• Selected topics in e^+e^- collisions
• Pion Form Factor in QCD Sum Rules with Nonlocal Condensates and in the Local-Duality Approach

Cited by in corpus (11)

• Universal behaviour of the ${\gamma }^{\ast }\gamma \to ({\pi }^0,\eta ,{\eta }^{\prime })$ transition form factors
• The ${\gamma }^{\ast }{\gamma }^{\ast }\to {\eta }_c$ transition form factor
• Local-duality QCD sum rules for strong isospin breaking in the decay constants of heavy-light mesons
• Advances in QCD sum rule calculations
• On properties of the exotic hadrons from QCD sum rules
• Local-Duality QCD Sum Rules for Pion Elastic and (pi^0, eta, eta') to gamma gamma* Transition Form Factors Revisited
• Pion Elastic and pi to gamma gamma* Transition Form Factors at Large Momentum Transfers
• Pion Elastic Form Factor in a Rather Broad Range of Momentum Transfers from Local-Duality QCD Sum Rule
• Elastic and transition form factors of light pseudoscalar mesons from QCD sum rules
• Recent results in QCD sum rule calculations of heavy meson properties
• On the description of exotic hadron states within QCD sum rules