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arXiv · hep-th/0503180

Two-loop superstrings and S-duality

Eric D'Hoker·Michael Gutperle·D. H. Phong
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Abstract

The two-loop contribution to the Type IIB low energy effective action term $D^4 R^4$, predicted by SL(2,Z) duality, is compared with that of the two-loop 4-point function derived recently in superstring perturbation theory through the method of projection onto super period matrices. For this, the precise overall normalization of the 4-point function is determined through factorization. The resulting contributions to $D^4 R^4$ match exactly, thus providing an indirect check of SL(2,Z) duality. The two-loop Heterotic low energy term $D^2F^4$ is evaluated in string perturbation theory; its form is closely related to the $D^4 R^4$ term in Type II, although its significance to duality is an open issue.

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Eric D'Hoker, Michael Gutperle, D. H. Phong. 2005-03-23. Two-loop superstrings and S-duality. https://doi.org/10.1016/j.nuclphysb.2005.06.010

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