Constraints on String Resonance Amplitudes

We perform a global analysis of the tree-level open-string amplitudes in the limit $s<<M_S^2$ . Based on the present data from the Tevatron, HERA, and LEP~2, we set a lower limit on the string scale $M_S>=0.69-1.96$ TeV at 95 % confidence level for the Chan-Paton factors $\mathrm{\mid }T\mathrm{\mid }=0-4$. We also estimate the expected sensitivities at the LHC, which can be as high as 19 TeV for $\mathrm{\mid }T\mathrm{\mid }=4$.