  We clarify inflaton models by considering them as effective field theories in
the Ginzburg-Landau spirit.In this new approach, the precise form of the
inflationary potential is constructed from the present WMAP data, and a useful
scheme is prepared to confront with the forthcoming data. In this approach, the
WMAP statement excluding the pure phi^4 potential implies the presence of an
inflaton mass term at the scale m sim 10^{13}GeV. Chaotic, new and hybrid
inflation is studied in an unified way. In all cases the inflaton potential
takes the form V(phi) = m^2 M_{Pl}^2 v(phi/M_{Pl}), where all coefficients in
the polynomial v(x) are of order one. If such potential corresponds to super
symmetry breaking, the susy breaking scale is sqrt{m M_{Pl}} \sim 10^{16}GeV
which turns to coincide with the GUT scale. The inflaton mass is therefore
given by a see-saw formula m sim M_{GUT}^2/M_{Pl}. The observables turn to be
two valued functions: one branch corresponds to new inflation and the other to
chaotic inflation,the branch point being the pure quadratic potential.For red
tilt spectrum, the potential which fits the best the present data and which
best prepares the way for the forthcoming data is a trinomial polynomial
withnegative quadratic term (new inflation).For blue tilt spectrum, hybrid
inflation turns to be the best choice. In both cases we find a formula relating
the inflaton mass with the ratio r of tensor/scalar perturbations and the
spectral index ns of scalar perturbations: 10^6 m/M_{Pl}= 127 sqrt{r|1-n_s|}
;(the coefficient 127 follows from the WMAP amplitude.Implications for string
theory are discussed.
