A note on non-perturbative R^4 couplings
High Energy Physics - Theory
2009-10-31 v2
Abstract
Exact non-perturbative results have been conjectured for R^4 couplings in type II maximally supersymmetric string theory. Strong evidence has already been obtained, but contributions of cusp forms, invisible in perturbation theory, have remained an open possibility. In this note, we use the D=8 N=2 superfield formalism of Berkovits to prove that supersymmetry requires the exact R^4 threshold to be an eigenmode of the Laplacian on the scalar manifold with a definite eigenvalue. Supersymmetry and U-duality invariance then identify the exact result with the order-3/2 Eisenstein series, and rule out cusp form contributions.
Keywords
Cite
@article{arxiv.hep-th/9804023,
title = {A note on non-perturbative R^4 couplings},
author = {B. Pioline},
journal= {arXiv preprint arXiv:hep-th/9804023},
year = {2009}
}
Comments
6 pages, uses amsmath and amssymb; typo in eq.(2) corrected; final version to be published in Phys. Lett. B