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arXiv · hep-th/0209068

On-shell S-matrix and tachyonic effective actions

Mohammad R. Garousi
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Abstract

We evaluate various disk level four-point functions involving the massless scalar and tachyon vertex operators in the presence of background B-flux in superstring theory. By studying these amplitudes in specific limits, we find couplings of two scalars with two tachyons, and couplings of four tachyons on the world-volume of non-BPS D-branes of superstring theory. They are fully consistent with the non-commutative tachyonic Dirac-Born-Infeld effective action. They also fix the coefficient of $T^4$ term in the expansion of the tachyon potential around its maximum.

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Mohammad R. Garousi. 2003-03-24. On-shell S-matrix and tachyonic effective actions. https://doi.org/10.1016/s0550-3213(02)00903-3

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