Note that the above discussions assume that all the MSSM degrees of freedom are in thermal equilibrium instantly right after inflation, however this basic assumption is in con- tradiction in presence of MSSM flat directions [122], which alters the thermal history of the universe and also affects the gravitino abundance. 2. Gauge singlet inflaton couplings to MSSM Within MSSM there exists two gauge-invariant combinations of only two superfields: H$_{u}$H$_{d}$, H$_{u}$L. (414) The combinations which include three superfields are: H$_{u}$Qu, H$_{d}$Qd, H$_{d}$Le, QLd, udd, and LLe. (415) SUSY together with gauge symmetry requires that the inflaton (a SM gauge singlet) su- perfield be coupled to these combinations. The superpotential terms Φ H$_{u}$H$_{d}$ and Φ H$_{u}$L have dimension four, and hence are renormalizable. On the other hand, the interaction terms that couple the inflaton to the combinations with three superfields have dimension five and are non-renormalizable. In following we focus on renormalizable interactions of the inflaton with matter which play the dominant role in its decay. Further note that terms representing gauge-invariant coupling of the inflaton to the gauge fields and gauginos are also of dimension five, and hence preheating into them will be suppressed $^{92}$. Preserving R -parity at the renormalizable level further constrains inflaton couplings to matter. Note that H$_{u}$H$_{d}$ is assigned +1 under R -parity, while H$_{u}$L has the opposite as- signment − 1. Therefore only one of the couplings preserves R -parity: Φ H$_{u}$H$_{d}$ if R$_{Φ}$ = +1, and Φ H$_{u}$L . If R$_{Φ}$ = − 1 (such as models where the RH sneutrino plays the role of the inflaton [783]). Therefore the renormalizable inflaton coupling to matter can be represented as [123]: 2 g Φ H$_{u}$ Ψ (416) hidden sectors, where one naturally obtains the expected value of B$_{3}$$_{/}$$_{2}$ ∼ 10 − 2 [815]. 92 It is possible that the inflaton mainly decays to another singlet (for example, the RH neutrinos) superfield, however, the underlying interactions of a gauge singlet to the MSSM superfields do not change. One must transfer the inflaton energy into the MSSM sector at any cost. 194