Higher dimensional extremal black strings
  We investigate the five and six-dimensional black strings within Einstein-Maxwell theory. The extremal black strings are endowed with the null Killing symmetry. We study the propagation of Einstein-Maxwell modes in the extremal black string background by using this symmetry. It turns out that one graviton is a propagating mode, while both the Maxwell $F$ and three-form $H$ fields are non-propagating modes. Further we discuss the stability and classical hair of the extremal black strings. 
H.W. Lee, Y.S. Myung(Inje U.), Jin Young Kim(Dongseo U.), D. K.   Park(Kyungnam U.)