Line functional theory for strings. II. Spins and symmetries

In the preceding paper we defined string field theory as a theory of line functionals (functions of geometric lines) which reproduces classical string dynamics in the Dirac form. This necessitates the introduction of new generalizations of the Dirac algebra, whose group-theoretic properties are analyzed in detail. The spin content of string fields in reduced four-dimensional spacetime is completely determined. Transformation laws of string fields under discrete symmetry operations such as charge conjugation (C), parity (P), and time reversal (T) are also given. It is found that the requirement of invariance of the string field action under C, T, and P severely restricts the possible forms of the generalized Dirac algebra