One-Loop Tachyon Amplitude in Unoriented Open-Closed String Field Theory

TL;DR

This paper computes one-loop tachyon amplitudes in unoriented open-closed string field theory, confirming the consistency of interaction couplings and the necessity of an SO(8192) gauge group.

Contribution

It provides the first detailed calculation of one-loop tachyon amplitudes and determines all interaction coupling constants in the theory.

Findings

Planar, nonplanar, and nonorientable amplitudes are correctly reproduced.

Coupling constants satisfy nontrivial consistency conditions.

Gauge group must be SO(8192).

Abstract

We calculate one-loop 2-point tachyon amplitudes in unoriented open-closed string field theory, and determine all the coupling constants of the interaction vertices in the theory. It is shown that the planar, nonplanar and nonorientable amplitudes are all reproduced correctly, and nontrivial consistencies between the determined coupling constants are observed. The necessity for the gauge group to be SO(2^{13}=8192) is also reconfirmed.