Conformal a-charge, correlation functions and conical defects
  In this note we demonstrate that, as we conjectured earlier in [1], the a-charge in the conformal anomaly in dimension $d=2n$ manifests in a $n$-point correlation function of energy momentum tensor of a CFT considered in flat spacetime with a conical defect. We consider in detail dimensions $d=2,\, 4,\, 6$ and give a general formula for arbitrary $n$. 
Sergey N. Solodukhin
hep-th cond-mat.stat-mech gr-qc