EPJ Web of Conferences (Jan 2020)

η’ beam asymmetry at threshold using the BGO-OD experiment

  • Alef Stefan,
  • Bauer Patrick,
  • Beck Reinhard,
  • Braghieri Alessandro,
  • Cole Philip,
  • Di Salvo Rachele,
  • Elsner Daniel,
  • Fantini Alessia,
  • Freyermuth Oliver,
  • Ghio Francesco,
  • Gridnev Anatoly,
  • Hammann Daniel,
  • Hannappel Jürgen,
  • Jude Thomas,
  • Kohl Katrin,
  • Kozlenko Nikolay,
  • Lapik Alexander,
  • Levi Sandri Paolo,
  • Lisin Valery,
  • Mandaglio Giuseppe,
  • Messi Roberto,
  • Moricciani Dario,
  • Nedorezov Vladimir,
  • Novinsky Dmitry,
  • Pedroni Paolo,
  • Polonski Andrei,
  • Reitz Björn-Eric,
  • Romaniuk Mariia,
  • Scheluchin Georg,
  • Schmieden Hartmut,
  • Sumachev Victorin,
  • Tarakanov Viacheslav,
  • Tillmanns Christian

DOI
https://doi.org/10.1051/epjconf/202024101002
Journal volume & issue
Vol. 241
p. 01002

Abstract

Read online

The unexpected nodal structure of the beam asymmetry recently reported by the GRAAL collaboration in η′ photoproduction very close to threshold could be explained by a previously unobserved narrow resonance. The BGO-OD experiment is ideally suited to verify this measurement via the detection of forward going charged particles which in the threshold region of interest allows the identification of the reaction γp → η′ p solely based on the proton going in the forward direction. This yields unprecedented statistics if, in the missing mass analysis of the η′ meson, the background can be sufficiently well controlled. Preliminary results using a linearly polarised photon beam are shown. The reaction γp → η′ p was identified in the BGO forward spectrometer, with simulated data used to seperate signal and background.