Extended Massive Ambitwistor String II
Abstract
This article continues previous work done in arXiv:2406.01907. It is shown in more detail how vacuum partition functions and the cosmological constant vanish at all orders of perturbation theory. Further, all-multiplicity higher-loop amplitudes are given and shown to be modular invariant, to have proper factorization, and to be UV-finite at least up to one-loop level, formally even to all levels. Therefore, the model provides a modular invariant and unitary N=8 supergravity theory in twistor space with embedded Super-Yang-Mills and promising UV-finiteness behavior.
Cite
@article{arxiv.2502.03581,
title = {Extended Massive Ambitwistor String II},
author = {Christian Kunz},
journal= {arXiv preprint arXiv:2502.03581},
year = {2026}
}
Comments
46 pages, v2 and v3 have changes to appendix A, in v4 the auxiliary part of the action expands the little group to contain a redundant 'tiny group', in v5 change of boundary conditions of ghost fields for manifest modular invariance with the consequence that loop amplitudes on odd spin structures no longer vanish, also improvements dealing with the expanded little group, and some other corrections