Prescriptions for Off-Shell Bosonic String Amplitudes

TL;DR

This paper presents simplified methods within bosonic string theory to compute off-shell amplitudes at tree and one-loop levels, connecting string results to known field theory vertices and properties.

Contribution

It introduces new prescriptions for calculating off-shell string amplitudes that match field theory results and satisfy transversality at one-loop.

Findings

Tree-level three-open-string amplitude matches three-gluon vertex in field theory.

One-loop two-string amplitude satisfies transversality.

Methods simplify off-shell amplitude computations in bosonic string theory.

Abstract

We give, in the framework of the bosonic string theory, simple prescriptions for computing, at tree and one-loop levels, off-shell string amplitudes for open and closed string massless states. In particular we obtain a tree amplitude for three open strings that in the field theory limit coincides with the three-gluon vertex in the usual covariant gauge and two-string one-loop amplitudes satisfying the property of transversality.