Smooth double crossing of the phantom barrier wΛ​=−1 has been
found possible in cosmological model with Gauss-Bonnet-scalar interaction, in
the presence of background cold dark matter. Such crossing has been observed to
be a sufficiently late time phenomena and independent of the sign of
Gauss-Bonnet-scalar interaction. The luminosity distance versus redshift curve
shows a perfect fit with the ΛCDM model up to z=3.5.Comment: 9 pages, 9 figure