Time-delay at higher genus in high-energy open string scattering

We explore some aspects of causal time-delay in open string scattering studied recently by Seiberg, Susskind and Toumbas. By examining high-energy scattering amplitudes at higher order in perturbation theory, we argue that causal time-delay at Gth order is 1/(G+1) times smaller than the time-delay at tree level. We propose a space–time interpretation of the result by utilizing the picture of the high-energy open string scattering put forward by Gross and Mañes. We argue that the phenomenon of reduced time-delay is attributed to the universal feature of the space–time string trajectory in high-energy scattering that string shape at higher order remains the same as that at tree level but overall scale is reduced. We also discuss implications to the space–time uncertainty principle and make brief comments on causal time-delay behavior in space/time noncommutative field theory.