page_title: Vector meson dominance
section_title: Background
hierarchical_section_title: Vector meson dominance / Background
caption_attribution_description: English: Hadronic contribution to the photon propagator in the VMD model
context_page_description: In physics, vector meson dominance was a model developed by J. J. Sakurai in the 1960s before the introduction of quantum chromodynamics to describe interactions between energetic photons and hadronic matter.
  In particular, the hadronic components of the physical photon consist of the lightest vector mesons, and. Therefore, interactions between photons and hadronic matter occur by the exchange of a hadron between the dressed photon and the hadronic target.
context_section_description: Measurements of the interaction between energetic photons and hadrons show that the interaction is much more intense than expected by the interaction of merely photons with the hadron's electric charge. Furthermore, the interaction of energetic photons with protons is similar to the interaction of photons with neutrons in spite of the fact that the electric charge structures of protons and neutrons are substantially different.
  According to VMD, the photon is a superposition of the pure electromagnetic photon (which interacts only with electric charges) and vector meson.
  Just after 1970, when more accurate data on the above processes became available, some discrepancies with the VMD predictions appeared and new extensions of the model were published. These theories are known as Generalized Vector Meson Dominance theories (GVMD).
caption: Hadronic contribution to the photon propagator in the VMD model
exif: {}