Is S=1 for c=1?

TL;DR

This paper demonstrates that the c=1 string in Liouville field theory has a nontrivial tree-level S-matrix that satisfies unitarity and factorization when all massive physical states are considered.

Contribution

It reveals the nontrivial S-matrix structure of the c=1 string in Liouville theory, emphasizing the importance of including all massive states.

Findings

The c=1 string has a nontrivial tree-level S-matrix.

The S-matrix satisfies unitarity and factorization.

Including all massive physical states is crucial for these properties.

Abstract

The $c=1$ string in the Liouville field theory approach is shown to possess a nontrivial tree-level $S$-matrix which satisfies factorization property implied by unitary, if all the extra massive physical states are included.