Near-horizon brane-scan revived

Abstract

In 1987 two versions of the brane-scan of D-dimensional super p-branes were put forward. The first pinpointed those (p,D) slots consistent with kappa-symmetric Green-Schwarz type actions; the second generalized the "membrane at the end of the universe" idea to all those superconformal groups describing p-branes on the boundary of AdS_{p+2} x S^{D-p-2}. Although the second version predicted D3 and M5 branes in addition to those of the first, it came unstuck because the 1/2 BPS solitonic branes failed to exhibit the required symmetry enhancement in the near-horizon limit, except in the non-dilatonic cases (p=2,D=11), (p=3,D=10) and (p=5,D=11). Just recently, however, it has been argued that the fundamental D=10 heterotic string does indeed display a near-horizon enhancement to OSp(8|2) as predicted by the brane-scan, provided alpha' corrections are taken into account. If this logic could be extended to the other strings and branes, it would resolve this 21-year-old paradox and provide new AdS/CFT dualities, which we tabulate.