suppressed (see Eq. (226)) and the predicted value for n$_{s}$ is very close to unity, n$_{s}$ ≃ 1 − . This value is precisely in agreement with the observations when cosmic strings are formed, if they contribute significantly to the generation of the anisotropies [263]. When the VEVs are not negligible compared to the Planck scale, SUGRA effects become important and may ruin the flatness of the inflaton potential. Indeed, the potential is now given by Eq. (135), the F -terms containing an additional exponential factor. The soft breaking mass of the scalar fields are typically [325, 326, 505, 512, 612, 614, 624–629] Once the inflaton gains a mass ∼ H , the contribution to the second slow-roll parameter η is of order unity and the field simply rolls down to the minimum of the potential and inflation stops, where m 2 SUGRA ≈ m 2 susy + ( V$_{susy}$/ 3 M 2 $_{P}$) ∼ m 2 susy + O (1) H $^{2}$, where m$_{susy}$ ∼ O (100) GeV contains soft-SUSY breaking mass term for low scale SUSY breaking scenarios. For VEVs smaller than the Planck scale it is always possible to obtain ϵ ≪ 1, but in SUGRA η can never be made less than one for a single chiral field with minimal kinetic terms $^{62}$. This is known as the η problem in SUGRA models of inflation [325, 326, 512]. When there are more than one chiral superfields, as in the F -term hybrid model, it can be possible to cancel the dominant O (1) H correction to the inflaton mass by choosing an appropriate K¨ ahler term [512, 627]. In hybrid inflation models derived from an F - term the dominant O (1) H correction in the mass term can be cancelled if | S | = 0 exactly, which however seems to lead to an initial condition problem, as discussed above. The fact that the superpotential is linear in S (as in Eq. (219)) guarantees the cancellation of the dominant contribution in the mass term for a minimal K¨ ahler, K$_{min}$ (Ψ$_{i}$ , Ψ ∗ $_{i}$) = ∑ Ψ$_{i}$Ψ ∗ i = 62 Except when m$_{inf}$ ≫ H$_{inf}$ . This can be realizable in an inflection point inflation as in the case of MSSM inflation, see Sec. V B 2. 103 4. SUGRA corrections to F -term inflation m 2 soft ∼ V 3 M 2 P ∼ O (1) H $^{2}$. (227) | η | ≡ M 2 P V ′′ V ∼ m 2 SUGRA H 2 ∼ O (1) , (228)