An ansatz for a non-perturbative four-graviton amplitude in type IIB superstring theory
Abstract
A natural SL(2,Z)-invariant generalization of the Veneziano amplitude in type IIB superstring theory is investigated. It includes certain perturbative and non-perturbative (D-instanton) contributions, and it reduces to the correct expressions in different limits. The singularities are poles in the s-t-u channels, corresponding to the exchange of particles with a mass spectrum coinciding with that of (p,q) string states. We describe the general structure of the associated perturbative corrections to the effective action.
- Publication:
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Physics Letters B
- Pub Date:
- January 1998
- DOI:
- 10.1016/S0370-2693(97)01417-2
- arXiv:
- arXiv:hep-th/9707241
- Bibcode:
- 1998PhLB..417..253R
- Keywords:
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- High Energy Physics - Theory
- E-Print:
- Version appeared in Phys.Lett. B. Discussion expanded. 7 pages, harvmac