Total cross section for the γd→π−ppreaction between 380 and 840 MeV

The total cross section for the γd→${\mathrm{\pi }}^{\mathrm{-}}$pp reaction has been measured for incident photon energies from 380 to 840 MeV in steps of 10 MeV, with the best energy resolution attained so far. A large-acceptance detector was used to observe the reaction products. Overall uncertainties in the deduced cross sections are less than 9% (∼4% statistical and ∼8% systematic). The results are in excellent agreement with previous bubble chamber measurements and do not show any statistically significant structure which can be interpreted as evidence for the formation of dibaryon resonances. An upper limit at 95% confidence level of ${\mathrm{\sigma }}_{\mathrm{peak}}$Γ<230 μb MeV is obtained for a resonance in the vicinity of photon energy 700 MeV (mass∼2490 MeV).