Factorization and Unitarity in Superstring Theory
arXiv:hep-th/0503248 · doi:10.1088/1126-6708/2005/08/058
Abstract
The overall coefficient of the two-loop 4-particle amplitude in superstring theory is determined by making use of the factorization and unitarity. To accomplish this we computed in detail all the relevant tree and one-loop amplitudes involved and determined their overall coefficients in a consistent way.
LaTex file, 19 pages, 4 figures; v2, minor corrections and figures corrected; v3, minor corrections with the English, to be published in JHEP