I will explain recent work with S. Mizera in which we give explicit evaluations of one-loop open string amplitudes at finite alpha’. Our method involves various deformations of the contour integral over the modular parameter. We directly verify that the one-loop string amplitude satisfies unitarity constraints. I will show plots of the amplitude which allows us to explore physical conjectures about their behavior, especially at high energies.

https://princeton.zoom.us/j/97248927011?pwd=SWFiNWFwZWE5SUR4OUxvV0ZacVdWQT09