SPring-8

SPring-8 (an acronym of Super Photon Ring – 8 GeV) is a synchrotron radiation facility located in Hyōgo Prefecture, Japan and run by the Japan Synchrotron Radiation Research Institute. The machine consists of a storage ring containing an 8 GeV electron beam. The beam is extracted and run through undulators to produce synchrotron radiation with energies ranging from soft X-rays (300 eV) up to hard X-rays (300 keV). The synchrotron radiation produced at SPring-8 is used for materials analysis and biochemical protein characterization by many Japanese manufacturers and universities.

Together with the Advanced Photon Source at Argonne National Laboratory in the United States the European Synchrotron Radiation Facility in Grenoble, France and PETRA at DESY in Hamburg, Germany, it is one of the four large (beam energy greater than 5 GeV) synchrotron radiation facilities in the world.

Contents

Research

The Laser Electron Photon Experiment at SPring-8 (LEPS) is an experiment producing high-energy (GeV) photon beams by the backward Compton scattering of photons upon the 8 GeV electrons of the SPring-8 synchrotron. These are then used for various particle physics experiments on hadrons. The first beam was produced in 1999, and data-taking commenced in 2000.[1]

The collaboration is known for their reports of a resonance which they interpret as a Θ+
 pentaquark candidate made of two up quarks, two down quarks and a strange antiquark (uudds). The 2008 Review of Particle Physics of the Particle Data Group ruled out the existence of this resonance,[2] but new reports from LEPS indicate that the resonance could be seen in the γd → K+
K−
pn channel.[3] If confirmed, the Θ+
 would be the first discovered exotic baryon.

See also

References

  1. ^ T. Hotta (27 October 2009). "Laser Electron Photon Experiment at SPring-8". Osaka University. http://www.rcnp.osaka-u.ac.jp/Divisions/np1-b/index.html. Retrieved 2009-11-21. 
  2. ^ C. Amsler et al. (Particle Data Group) (2008). "Review of Particle Physics: Pentaquarks". Physics Letters B 667 (1): 1–1340. Bibcode 2008PhLB..667....1P. doi:10.1016/j.physletb.2008.07.018. http://pdg.lbl.gov/2008/reviews/pentaquarks_b801.pdf. 
  3. ^ T. Nakano et al. (LEPS collaboration) (2009). "Evidence of the Θ+ in the γd → K+K−pn reaction". Physical Review C 79 (2): 025210. arXiv:0812.1035. Bibcode 2009PhRvC..79b5210N. doi:10.1103/PhysRevC.79.025210. 

External links