THE ORBIFOLDS OF PERMUTATION-TYPE AS PHYSICAL STRING SYSTEMS AT MULTIPLES OF c = 26 II: THE TWISTED BRST SYSTEMS OF ${\hat c} = 52$ MATTER

This is the second in a series of papers which consider the orbifolds of permutation-type as candidates for new physical string systems at higher central charge. In the first paper, I worked out the extended actions of the twisted sectors of those orbifolds — which exhibit new permutation-twisted worldsheet gravities and correspondingly extended diffeomorphism groups. In this paper I begin the study of these systems as operator string theories, limiting the discussion for simplicity to the strings with [Formula: see text] matter (which are those governed by ℤ2-twisted permutation gravity). In particular, I present here a construction of the twisted reparametrization ghosts and new twisted BRST systems of all [Formula: see text] strings. The twisted BRST systems also imply new extended physical state conditions, whose analysis for individual [Formula: see text] strings is deferred to the next paper of the series.