Measurement of neutral pion photoproduction off the proton with the large acceptance electromagnetic calorimeter BGOegg

SPring-8 LEPS2 beamline: A facility to produce a multi-GeV photon beam via laser Compton scattering

“…Physics data-taking using a liquid hydrogen or carbon target was done from 2014 to 2016. So far, we have shown results in the analyses searching for baryon resonances and mesic nuclei [30,31,32].…”

“…The measured transmittance is in agreement with the value calculated from the amount of materials. So far, we have observed a phenomenon in which the transmittance depends on the photon beam energy when the focal point of incident laser light shifts farther than the design, causing the cut-off of a lower-energy and more-widespread component of the photon beam at the lead collimator [30,40]. Therefore, it is important to monitor the laser focal point through the confirmation of no existence of energy dependence in the transmittance measured with this system.…”

Light Baryon Spectroscopy

“…Copyright 2006 by the American Physical Society. Right: The LEPS2/BGOegg experimental setup [144]. Reprinted figure with permission from [144].…”

“…Right: The LEPS2/BGOegg experimental setup [144]. Reprinted figure with permission from [144]. Copyright 2019 by the American Physical Society.…”

“…As a first example, it is worth mentioning the beam asymmetry measurements by the CLAS collaboration from 2013 [181] and BGOegg at LEPS2 from 2019 [144]. By using a linearly polarized photon beam on an unpolarized proton target, the beam asymmetry could be extracted over a wide energy range with a low statistical uncertainty.…”