Upper limit for DD production in pp interactions at C.M. energy of 55 GeV

From a search for e^±μ^± production at the CERN ISR an upper limit of 0.92 μb (95% confidence limit) has been inferred for σ·B_e·B_μ for the reaction $\text{p}\text{+}\text{p}\text{→}\text{D}\text{+}\text{D}\text{+}\text{X}\text{at}\text{√s}\text{of}\text{55}\text{GeV}$.