Dynamical scalar hair formation around a Schwarzschild black hole
  Scalar fields coupled to the Gauss-Bonnet invariant evade the known no-hair theorems and have nontrivial configurations around black holes. We focus on a scalar field that couples linearly to the Gauss-Bonnet invariant and hence exhibits shift symmetry. We study its dynamical evolution and the formation of scalar hair in a Schwarzschild background. We show that the evolution eventually settles to the known static hairy solutions in the appropriate limit. 
Robert Benkel, Thomas P. Sotiriou, Helvi Witek
gr-qc astro-ph.HE hep-th