The Orbifolds of Permutation-Type as Physical String Systems at Multiples of $c=26$ III. The Spectra of $\hat{c}=52$ Strings

Abstract

In the second paper of this series, I obtained the twisted BRST systems and extended physical-state conditions of all twisted open and closed $\hat{c} = 52$ strings. In this paper, I supplement the extended physical-state conditions with the explicit form of the extended (twisted) Virasoro generators of all $\hat{c} = 52$ strings, which allows us to discuss the physical spectra of these systems. Surprisingly, all the $\hat{c}=52$ spectra admit an equivalent description in terms of generically-unconventional Virasoro generators at $c=26$. This description strongly supports our prior conjecture that the $\hat{c}=52$ strings are free of negative-norm states, and moreover shows that the spectra of some of the simpler cases are equivalent to those of ordinary untwisted open and closed $c=26$ strings.