It is shown that an orbifold-like construction based on an external automorphism yields the E8 model when applied to several 10-dimensional heterotic strings. The decomposition of the internal space into direct products of level two Ě8 and critical Ising representations is given. All characters and string functions of level-two Ě8 representations are derived explicitly. The conformal field theory underlying the E8 string is determined in detail. We also elucidate the role of modular invariance in the apparent uniqueness of the E8 string.
ASJC Scopus subject areas
- Nuclear and High Energy Physics