Static, four-dimensional (4-d) black holes (BH's) in (4+n)-d Kaluza-Klein
(KK) theory with Abelian isometry and diagonal internal metric have at most one
electric (Q) and one magnetic (P) charges, which can either come from the
same U(1)-gauge field (corresponding to BH's in effective 5-d KK theory) or
from different ones (corresponding to BH's with U(1)M×U(1)E isometry
of an effective 6-d KK theory). In the latter case, explicit non-extreme
solutions have the global space-time of Schwarzschild BH's, finite temperature,
and non-zero entropy. In the extreme (supersymmetric) limit the singularity
becomes null, the temperature saturates the upper bound
TH=1/4π∣QP∣, and entropy is zero. A class of KK BH's with
constrained charge configurations, exhibiting a continuous electric-magnetic
duality, are generated by global SO(n) transformations on the above classes
of the solutions.Comment: 11 pages, 2 Postscript figures. uses RevTeX and psfig.sty (for figs)
paper and figs also at ftp://dept.physics.upenn.edu/pub/Cvetic/UPR-645-