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Marcel Vonk, CAMGSD

Field theory structures in string theory amplitudes

Recently, several new techniques have been developed which allow one to much more efficiently calculate scattering amplitudes in gauge theories. The general lesson from these techniques seems to be that for gauge theories, Feynman diagram expansions are often not the most efficient tool to calculate scattering amplitudes. Instead, one should use structures such as the helicity configuration of the amplitude and analyticity in the external momenta. In this talk, I discuss how many of these observations carry over directly from gauge theories to open string theory, and how they can be used to calculate alpha'-corrections to effective field theory amplitudes. It turns out that, viewed as an effective quantum field theory, open string theory may actually be much simpler and more elegant than one would expect.