Reheating predictions in constant-roll inflation models

Auxiliary predictions of inflation models can be derived from reheating by considering the expansion history of the CMB pivot scales. In this paper, we study the reheating predictions of the constant-roll inflation models with eta V = constant and eta over bar = constant instead of the usual eta H = constant. This is because inflation in the eta H = constant inflation model cannot end naturally. We find that when eta V <= 0 and eta over bar <= 0, the reheating gives almost the same predictions for both models, and the instantaneous reheating is allowed. For the case of eta over bar > 0 the ending of inflation cannot occur too. When eta V > 0, the instantaneous reheating for the eta V = constant inflation model is prohibited and this inflation model is compatible with the Planck CMB observations only at the 2a margin. Finally, we find that the reheating process requires that eta V and eta over bar should satisfy -0.1 < eta V < 0.03 and -0.1 < eta over bar <= 0. (c) 2022 Elsevier B.V. All rights reserved.