Search for narrow dibaryon resonances in neutral pion photoproduction from the deuteron

The reaction gammad --> pi X-0 has been measured with TAPS at MAMI in the energy range E-gamma = 140-300 MeV. Using the Glasgow tagging spectrometer a photon energy resolution of 0.8 MeV was achieved. The energy excitation functions of integral and differential total cross-sections show no structures of statistical significance > 2 sigma. Upper limits for the production of narrow isoscalar or isovector dibaryons with masses m less than or equal to 2100 MeV/c(2) were deduced. They are in the range 2-5 mub averaged over the 0.8 MeV energy resolution.