We present here the effective theory of inflation `a la Ginsburg-Landau in
which the inflaton potential is a polynomial. The slow-roll expansion becomes a
systematic 1/N expansion where N ~ 60. The spectral index and the ratio of
tensor/scalar fluctuations are n_s - 1 = O(1/N), r = O(1/N) while the running
turns to be d n_s/d \ln k = O(1/N^2) and can be neglected. The energy scale of
inflation M ~ 0.7 10^{16} GeV is completely determined by the amplitude of the
scalar adiabatic fluctuations. A complete analytic study plus the Monte Carlo
Markov Chains (MCMC) analysis of the available CMB+LSS data showed: (a) the
spontaneous breaking of the phi -> - phi symmetry of the inflaton potential.
(b) a lower bound for r: r > 0.023 (95% CL) and r > 0.046 (68% CL). (c) The
preferred inflation potential is a double well, even function of the field with
a moderate quartic coupling yielding as most probable values: n_s = 0.964, r =
0.051. This value for r is within reach of forthcoming CMB observations. We
investigate the DM properties using cosmological theory and the galaxy
observations. Our DM analysis is independent of the particle physics model for
DM and it is based on the DM phase-space density rho_{DM}/sigma^3_{DM}. We
derive explicit formulas for the DM particle mass m and for the number of
ultrarelativistic degrees of freedom g_d (hence the temperature) at decoupling.
We find that m turns to be at the keV scale. The keV scale DM is
non-relativistic during structure formation, reproduces the small and large
scale structure but it cannot be responsible of the e^+ and pbar excess in
cosmic rays which can be explained by astrophysical mechanisms (Abridged).Comment: 28 pages; to be published in the Lev Lipatov Festschrift on the
occasion of Lev's 70th birthday, `Subtleties in Quantum Field Theories', D.
Diakonov, Editor, Gatchina, Russia, 201