Correlation functions of the global E8 symmetry currents in the   Heterotic 5-brane theory
  We consider the 5-brane placed at one end of the world in the Heterotic $E_8 \times E_8$ theory. The low energy theory is a 6 dimensional $(1,0)$ superconformal theory with $E_8$ as a global symmetry. We calculate the two-point correlator of the $E_8$ current in 6 dimensions and in 4 dimensions after compactification on $\MT{2}$. This correlator is derived in 3 different ways: From field theory, from 11 dimensional supergravity and from F-theory. 
Morten Krogh