A Self-Tuning Solution of the Cosmological Constant Problem
  We discuss the four-dimensional cosmological constant problem in a five-dimensional setting. A scalar field coupled to the SM forms dynamically a smooth brane with four-dimensional Poincare invariance, independently of SM physics. In this respect, our solution may be regarded as a self-tuning solution, free of any singularities and fine-tuning problems. 
A. Kehagias and K. Tamvakis