ABSTRACT
When d = 11 supergravity spontaneously compactifies to d = 4. the number of unbroken sypersymmetries. 0 ⩽ N ⩽ 8. is determined by the holonomy group, ℋ of the d = 7 ground-state connection. Here we present a new solution: Minkowski spacetime × K3 × T3, for which ℋ = SU(2) and N = 4. The massless sector in d = 4 is given by N = 4 supergravity coupled to 22 N = 4 vector multiplets. Aside from its intrinsic interest, this example throws new light on Kaluza–Klein supergravity. In particular, we note that the 192 + 192 massless degrees of freedom obtained from K3 × T3 exceed the 128 + 128 of the N = 8 theory obtained from T7 or S7.
