Hadronic Form Factors and Perturbative QCD

Abstract

The electromagnetic form factors of hadrons at large momentum transfer have been the subject of intense theoretical and experimental scrutiny over the past two decades, yet there is still not a universally-accepted framework for their description. This review is a synopsis of their current status at large momentum transfer. The basic theoretical approaches to form factors at large momentum transfer are developed, emphasizing the valence quark and Feynman (soft) pictures. The discussion includes the relation of these descriptions to the parton model, as well as the roles of factorization, evolution, Sudakov resummation and QCD sum rules. This is followed by a discussion of the experimental status of pion and nucleon elastic form factors and resonance production amplitudes in the light of recent data, highlighting the successes and shortcomings of various theoretical proposals.

28 pages, LateX, 11 epsf figures. To appear In Annual Review of Nuclear and Particle Science, 1997

Cited by in corpus (42)

• Determination of the pion charge form factor for Q^2=0.60-1.60 GeV^2
• Higher Twist Distribution Amplitudes of the Nucleon in QCD
• gamma* N -> Delta transition form factors: a new analysis of the JLab data on p(e,e'p)pi0 at Q^2=2.8 and 4.0 (GeV/c)^2
• Direct measurement of the pion valence quark momentum distribution, the pion light-cone wave function squared
• Observation of color-transparency in diffractive dissociation of pions
• QCD analysis of bar p N -> gamma* pi in the scaling limit
• Study of N* Production from J/Psi--> p pbar eta
• D-state effects in the electromagnetic N-Delta transition
• Valence quark contributions for the gamma N -> P11(1440) form factors
• Computing Light-Front Wave Functions Without Light-Front Quantization: A Large-Momentum Effective Theory Approach
• Approach to Perturbative Results in the N-Delta Transition
• Perturbative Duality in the Resonance Spin Structure Functions
• Soft pion theorem for hard near threshold pion production
• Exclusive meson pair production in gamma* gamma scattering at small momentum transfer
• Backward electroproduction of pi0 mesons on protons in the region of nucleon resonances at four momentum transfer squared Q**2 = 1.0 GeV**2
• Instanton Contribution to the Pion Electro-Magnetic Formfactor at Q^2 > 1 GeV^2
• Holography at work for nuclear and hadron physics
• Baryon form factors at high momentum transfer and generalized parton distributions
• Preliminaries on a Lattice Analysis of The Pion Light-cone Wave function: a Partonic Signal?
• Transition Radiation in QCD matter
• Perturbative Color Transparency in Electroproduction Experiments
• Real and Virtual Compton Scattering off the Nucleon
• ALP production in weak mesonic decays
• The pion distribution amplitude and the pion-photon transition form factor in a nonlocal chiral quark model
• Real and Virtual Nucleon Compton Scattering in the Perturbative Limit
• Proton Electro-Magnetic Form-Factors in the Instanton Liquid Model
• Pion form factor and QCD sum rules: case of pseudoscalar current
• Power corrections to the ${\pi }^0\gamma$ transition form factor and pion distribution amplitudes
• The P_33(1232) resonance contribution into the amplitudes M_{1+}^{3/2},E_{1+}^{3/2},S_{1+}^{3/2} from an analysis of the p(e,e'p)π^0 data at Q^2 = 2.8, 3.2, and 4 (GeV/c)^2 within dispersion relation approach
• Exploring twist-4 chiral-even GPDs in the light-front quark-diquark model
• Deeply Virtual Neutrino Scattering (DVNS)
• Measurement of the Pion and Photon Light-Cone Wave Functions by Diffractive Dissociation
• Measurement of Light-Cone Wave Functions by Diffractive Dissociation
• Electromagnetic Pion and Nucleon Form Factors at Positive and Negative $q^2$ Within the Framework of Quark-Gluon Strings Model
• Generalized parton distributions for the lowest-lying octet baryons
• Exclusive Hadronic Processes and Color Transparency
• Electromagnetic and Axial Current Form Factors and Spectroscopy of Three-Flavor Holographic Baryons
• QCD analysis of the $P$-wave charmonium electromagnetic Dalitz decays $h_c\to {\eta }^{(\prime )}{\ell }^{+}{\ell }^{-}$
• Covariant analysis of electromagnetic current on the light cone: exposition with scalar Yukawa theory
• Irreducible tensor approach to spin observables in photo production of mesons with arbitrary spin-parity $s^{\pi }$
• The pion electromagnetic structure with self-energy
• Deeply Virtual Neutrino Scattering at Leading Twist