the spectral index is strictly 0 . 92, for details see [89, 90, 711] $^{74}$. For α 2 < 0, the spectral index will be smaller than the 0 . 92, which is more than 3 σ away from observations. The more interesting case, as pointed out in [90, 711], happens for α 2 > 0. This happens for In Fig. (8), we have shown δ$_{H}$ as a function of n$_{s}$ for different values of m$_{φ}$ . The horizontal blue band shows the 2 σ experimental band for δ$_{H}$ . The vertical green shaded region is the 2 σ experimental band for n$_{s}$ . The region enclosed by solid lines shows the 1 σ experimental allowed region. Smaller values of m$_{φ}$ are preferred for smaller values of n$_{s}$ . Note that the allowed range of m$_{φ}$ is 90 − 330 GeV for the experimental ranges of n$_{s}$ and δ$_{H}$ . This figure is drawn for λ ≃ 1, which is natural in the context of effective field theory (unless it is suppressed due to some symmetry). Smaller values of λ will lead to an increase in m$_{φ}$ , see Fig. (9), where we have plotted ( n$_{s}$, m$_{φ}$ ) for different values of λ for the case of udd direction with different masses of m$_{u}$, m$_{d}$ , and fixed value of tan( β ). We will explain the blue bands when we discuss the parameter space of MSSM inflation at low energies close to the dark matter production scale [90, 714]. By embedding MSSM inflation in GUT makes a mild assumption that there exists new physics which encompasses MSSM beyond the unification scale M$_{G}$ . We remind the readers that inflation occurs around a flat direction VEV φ$_{0}$ ∼ 10 14 GeV. Since φ$_{0}$ ≪ M$_{G}$ , heavy GUT degrees of freedom play no role in the dynamics of MSSM inflation, and hence they can be ignored. Here we wish to understand how such embedding would affect inflationary scenario. It is generically believed that gravity breaks global symmetries [715]. Then all gauge invariant terms which are M$_{P}$ suppressed should appear with λ ∼ O (1). Obviously the 74 Varying range of spectral tilt is in concordance with the statistical nature of the vacua at low energies below the cut-off. MSSM harbors a mini-landscape [90] with a moduli space of 37 complex dimensions [407], which has more than 700 gauge invariant monomials [713]. Although, its much smaller compared to the string landscape, but one would naturally expect a distribution of discrete values of non-renormalizable A -terms along with the soft breaking terms. This would inevitably give rise to many realizations of our universe with varied range of spectral tilts. 2 × $_{10}$− 6 ≤ Δ 2 ≤ 5 . 2 × $_{10}$− $^{6}$. (329) 4. Embedding MSSM inflation in SU (5) or SO (10) GUT 149