Inflation with $f(R,\phi)$ in Jordan frame
  We consider an $f(R)$ action that is non-minimally coupled to a massive
scalar field. The model closely resembles scalar-tensor theory and by conformal
transformation can be transformed to Einstein frame. To avoid the ambiguity of
the frame dependence, we obtain an exact analytical solution in Jordan frame
and show that the model leads to a period of accelerated expansion with an
exit. Further, we compute the scalar and tensor power spectrum for the model
and compare them with observations.
