φ meson production experiments at SPring-8

A new facility for GeV photon beams in the energy range of Eγ 1.5 ∼ 3.5 GeV has been constructed at SPring-8. The GeV photons are produced via Compton backscattering, and used to study the sub-nucleonic structure of the nucleon. The main subject of this project is to search for the quark behavior in the nucleon - the building blocks of nucleons. Fundamental role of quark in nucleon or in a nucleus will be studied as the current topics to reveal the underlying basic principle. This SPring-8 project called Laser-Electron-Photon (LEP) project offers an unique opportunity to study the nucleon structure in view of the quark physics. Using the Compton backscattered photons induced by a short-wavelength laser light, the polarized GeV photons with a low emittance are generated. This special feature makes real-photon experiments complementary with electron-scattering experiments. The detector is especially designed to detect the forward events. (author)