On the Normalization and Hermiticity of Amplitudes in 4D Heterotic Superstrings

Abstract

We consider how to normalize the scattering amplitudes of 4D heterotic superstrings in a Minkowski background. We fix the normalization of the vacuum amplitude (the string partition function) at each genus, and of every vertex operator describing a physical external string state in a way consistent with unitarity of the $S$-matrix. We also provide an explicit expression for the map relating the vertex operator of an incoming physical state to the vertex operator describing the same physical state, but outgoing. This map is related to hermitean conjugation and to the hermiticity properties of the scattering amplitudes.

1+33 pages, TeX with macros included

References in corpus (5)

• Introduction to string field theory
• The Box Graph In Superstring Theory
• Dispersion Relations in String Theory
• On the computation of one-loop amplitudes with external fermions in 4d heterotic superstrings
• Bosonization of World-Sheet Fermions in Minkowski Space-Time

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• Multiloop ${\Phi }^3$ Amplitudes from Bosonic String Theory
• String Theory and the CPT Theorem on the World-Sheet
• CPT Invariance of String Models in a Minkowski Background
• On the Compton Scattering in String Theory
• On the Evaluation of Compton Scattering Amplitudes in String Theory
• Effectively Closed Infinite-Genus Surfaces and the String Coupling