Weyl Groups in AdS3/CFT2

Abstract

A system of D[1]- and D[5]-branes with a Kaluza-Klein momentum is re-investigated using the five-dimensional U-duality group E[6(+6)](Z).We show that the residual U-duality symmetry that keeps this D[1]-D[5]-KK system intact is generically given by a lift of the Weyl group of F[4(+4)], embedded as a finite subgroup in E[6(+6)](Z).We also show that the residual U-duality group is enhanced to F[4(+4)](Z) when all three charges coincide. We then apply the analysis to the AdS[3]/CFT[2] correspondence and discuss that among 28 marginal operators of CFT[2] which couple to massless scalars of AdS[3] gravity at the boundary, 16 would behave as exactly marginal operators for generic D[1]-D[5]-KK systems. This is shown by analyzing possible three-point couplings among the 4[2] Kaluza-Klein scalars with the use of their transformation properties under the residual U-duality group.