Cosmic expansion and growth histories in Galileon scalar-tensor models
  of dark energy
  We study models of late-time cosmic acceleration in terms of scalar-tensor
theories generalized to include a certain class of non-linear derivative
interaction of the scalar field. The non-linear effect suppress the
scalar-mediated force at short distances to pass solar-system tests of gravity.
It is found that the expansion history until today is almost indistinguishable
from that of the $\Lambda$CDM model or some (phantom) dark energy models, but
the fate of the universe depends clearly on the model parameter. The growth
index of matter density perturbations is computed to show that its past
asymptotic value is given by 9/16, while the value today is as small as 0.4.
