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decay to the i − th degree of freedom. The composition of the reheat plasma is therefore model-dependent before its complete thermalization. However, some general statements can be made based on symmetry arguments. 

During the quasi-adiabatic evolution of the reheated plasma, i.e., for H$_{thr}$ < H < Γ$_{d}$, we have 101 [122] 2 

In this epoch T varies in a range T$_{min}$ ≤ T ≤ T$_{max}$ , where T$_{max}$ ≈ m$_{φ}$/ 3 is reached right after the inflaton decay. Because of complete thermalization, T sharply drops from T$_{min}$ to T$_{R}$ at H$_{thr}$ , where the conservation of energy implies that 

## 1. Particle creation in a quasi-thermal phase 

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In this section, we wish to create weakly interacting χ particles from the scatterings of the MSSM particles during the quasi-thermal phase of the universe. Recall the Boltzmann equation governing the number density of χ particles, which is given by [96, 341]: 

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Here n$_{i}$ and n$_{j}$ are the number densities of the i − th and j − th particles, $^{σ$_{ij}$}$→ χ is the cross- section for producing χ from scatterings of i and j , and the sum is taken over all fields which participate in χ production. Also 〈 ... 〉 denotes averaging over the distribution. Since the production of χ quanta will be Boltzmann suppressed if T < m$_{χ}$/ 3. Therefore, in order to obtain the total number of χ quanta produced from scatterings, it will be sufficient to integrate the RH side of Eq. (438) from the highest temperature down to T$_{min}$ . The relic 

