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arXiv · 2407.15925

Non-analytic terms of string amplitudes from partial waves

Yu-tin Huang·Hynek Paul·Michele Santagata
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Abstract

We describe a general formalism based on the partial-wave decomposition to compute the iterative $s$-channel discontinuity of four-point amplitudes at any loop order. As an application, we focus on the low-energy expansions of type I and II superstring amplitudes. Besides providing new results for their leading and sub-leading logarithmic contributions beyond genus one, our approach elucidates the general structure of non-analytic threshold terms. In the case of open strings, the use of orthogonal colour projectors allows us to efficiently compute all contributions from different worldsheet topologies at a given loop order.

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Yu-tin Huang, Hynek Paul, Michele Santagata. 2024-07-22. Non-analytic terms of string amplitudes from partial waves. https://doi.org/10.1007/jhep11(2024)117

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