Physics Letters B (Dec 2016)

An experiment of X-ray photon–photon elastic scattering with a Laue-case beam collider

  • T. Yamaji,
  • T. Inada,
  • T. Yamazaki,
  • T. Namba,
  • S. Asai,
  • T. Kobayashi,
  • K. Tamasaku,
  • Y. Tanaka,
  • Y. Inubushi,
  • K. Sawada,
  • M. Yabashi,
  • T. Ishikawa

Journal volume & issue
Vol. 763
pp. 454 – 457

Abstract

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We report a search for photon–photon elastic scattering in vacuum in the X-ray region at an energy in the center of mass system of ωcms=6.5keV for which the QED cross section is σQED=2.5×10−47m2. An X-ray beam provided by the SACLA X-ray Free Electron Laser is split and the two beamlets are made to collide at right angle, with a total integrated luminosity of (1.24±0.08)×1028m−2. No signal X rays from the elastic scattering that satisfy the correlation between energy and scattering angle were detected. We obtain a 95% C.L. upper limit for the scattering cross section of 1.9×10−27m2 at ωcms=6.5keV. The upper limit is the lowest upper limit obtained so far by keV experiments.