Münster 2017 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 57: Hadron Structure and Spectroscopy VII
HK 57.5: Talk
Friday, March 31, 2017, 15:30–15:45, F 5
Status of the analysis of the η′→ωγ relative branching ratio — •Andreas Neiser and Wolfgang Gradl for the A2 collaboration — Institut für Kernphysik, Universität Mainz
The A2 collaboration at the electron accelerator MAMI in Mainz uses energy-tagged photons to produce light mesons off the nucleon. In 2014, three dedicated beamtimes for the production of η′ mesons off unpolarized protons yielded a data sample of ≈6×106 η′ mesons within an incident photon energy range Eγ=1.42…1.58 GeV.
The A2 detector system mainly consists of the 4π calorimeter Crystal Ball and the TAPS calorimeter in forward direction, which are ideally suited to detect neutral final states in the given energy range.
We present the status of the analysis for the relative branching ratio of the pseudoscalar-vector-gamma decay η′→ωγ to the reference channel η′→2γ. We show the extraction of the value based on Monte Carlo studies and give estimates of the expected uncertainties of our measurement. The result serves as an input to effective field theories of the strong interaction, especially concerning η-η′-mixing and the consistent inclusion of vector mesons.