ar X iv : h ep - p h / 02 12 33 1 v 1 2 2 D ec 2 00 2 BA - 02 - 40 Inflation and Leptogenesis with Five Dimensional SO ( 10 )

We present a five dimensional SO(10) model compactified on S/(Z2×Z ′ 2), which yields SU(3)c×SU(2)L×U(1)Y ×U(1)X below the compactification scale. The gauge symmetry SU(5) × U(1)X is preserved on one of the fixed points, while ‘flipped’ SU(5) × U(1)′X is respected on the other fixed point. Inflation is associated with U(1)X breaking, and is implemented through F-term scalar potentials on the two fixed points. A brane-localized Einstein-Hilbert term allows both branes to have positive tensions during inflation. The scale of U(1)X breaking is fixed from δT/T measurements to be around 10 16 GeV, and cosmic strings produced during U(1)X breaking are inflated away. The scalar spectral index n = 0.96−0.99, and there is negligible contribution ( ∼ 1%) from gravitational waves to the quadrupole anisotropy. The inflaton field decays into right-handed neutrinos whose subsequent out of equilibrium decay yields the observed baryon asymmetry via leptogenesis. [email protected] [email protected]