Recently there have been advances in observational constraints of gravity theories that contain scalars coupled to the gauss-bonnet topological term:
http://arxiv.org/abs/0704.0175
http://arxiv.org/abs/1204.4524
my understanding (from what the above authors are stating) is that a scalar coupled to the gauss-bonnet term is a natural low-energy coupling predicted by string theory, so this might be some indirect supporting evidence for string theory
my question is regarding the scalar field in this coupling: What are the string theory constraints (if any) on the mass of the scalar field particle associated with this coupling? Does it lie in an interval that we could be measuring in the LHC?
