Crossing w = −1 in Gauss–Bonnet Brane World with Induced Gravity^*

Recent type Ia supernovas data seemingly favor a dark energy model whose equation of state w(z) crosses −1 very recently, which is a much more amazing problem than the acceleration of the universe. In this paper we show that it is possible to realize such a crossing without introducing any phantom component in a Gauss–Bonnet brane world with induced gravity, where a four-dimensional curvature scalar on the brane and a five-dimensional Gauss–Bonnet term in the bulk are present. In this realization, the Gauss–Bonnet term and the mass parameter in the bulk play a crucial role.