Modular Groups for Twisted Narain Models

Abstract

We demonstrate how to find modular discrete symmetry groups for $Z_N$ orbifolds. The $Z_7$ orbifold is treated in detail as a non-trivial example of a $(2,2)$ orbifold model. We give the generators of the modular group for this case which, surprisingly, does not contain $\sltz^3$ as had been speculated. The treatment models with discrete Wilson lines is also discussed. We consider examples which demonstrate that discrete Wilson lines affect the modular group in a non-trivial manner. In particular, we show that it is possible for a Wilson line to break $SL(2,\mathbf{Z})$.

23 pages

References in corpus (2)

• Comment on the Generation Number in Orbifold Compactifications
• On the Moduli Space of the $T^6/Z_3$ Orbifold and Its Modular Group

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