ITP South Building 6420

Discrete symmetries do not have Noether currents, therefore how to detect the global anomaly is not obvious. In this talk we will introduce a new global anomaly for internal discrete symmetry in 2d CFTs and compute the anomaly using torus partition function with symmetry line insertions. We compare our anomaly free condition with orbifolding condition and symmetry invariant boundary state condition by focusing on minimal models and Wess-Zumino-Witten models.