Closed String S-matrix Elements in Open String Field Theory

TL;DR

This paper calculates specific closed string S-matrix elements within open string field theory and demonstrates they match the known disk-level results from perturbative string theory, confirming consistency between the formalisms.

Contribution

It provides explicit calculations of closed string S-matrix elements in open string field theory and proves their equivalence to perturbative string theory results.

Findings

Closed string S-matrix elements match disk-level perturbative results.

Explicit calculation of two closed strings and mixed open-closed string amplitudes.

Validation of open string field theory's consistency with perturbative string theory.

Abstract

We study the S-matrix elements of the gauge invariant operators corresponding to on-shell closed strings, in open string field theory. In particular, we calculate the tree level S-matrix element of two ${\it arbitrary}$ closed strings, and the S-matrix element of one closed string and two open strings. By mapping the world-sheet of these amplitudes to the upper half $z$-plane, and by evaluating explicitly the correlators in the ghost part, we show that these S-matrix elements are ${\it exactly}$ identical to the corresponding disk level S-matrix elements in perturbative string theory.