Higher-derivative couplings in string theory: five-point contact terms

TL;DR

This paper calculates specific higher-derivative couplings in type II string theory, revealing new structures at tree level that impact supersymmetry and duality properties, with tests on compactifications.

Contribution

It provides the first computation of tree-level $H^2R^3$ couplings in type II strings and uncovers new kinematical structures not seen in one-loop results.

Findings

Discovery of new kinematical structures at tree level

Implications for supersymmetry and duality in type II strings

Validation of couplings through compactification tests

Abstract

We compute the tree-level $H^2R^3$ couplings of type II strings and provide some basic tests of the couplings by considering both K3 and Calabi-Yau threefold compactifications. Curiously, additional kinematical structures show up at tree level that are not present in the one-loop couplings. This has interesting implications for type II supersymmetry as well as $SL(2, \mathbb Z)$ duality in type IIB strings.