LiteBIRD and CMB-S4 Sensitivities to Reheating in Plateau Models of Inflation

Abstract

We study the sensitivity of LiteBIRD and CMB-S4 to the reheating temperature and the inflaton coupling in three types of plateau-potential models of inflation, namely mutated hilltop inflation, radion gauge inflation, and α-attractor T models. We first study the relations between model parameters and CMB observables in all models analytically. We then perform Monte Carlo Markov Chain based forecasts to quantify the information gain on the reheating temperature, the inflaton coupling, and the scale of inflation that can be achieved with LiteBIRD and CMB-S4. We compare the results of the forecasts to those obtained from a recently proposed simple analytic method. We find that both LiteBIRD and CMB-S4 can simultaneously constrain the scale of inflation and the reheating temperature in all three types of models. They can for the first time obtain both an upper and lower bound on the latter, comprising the first ever measurement. In the mutated hilltop inflation and radion gauge inflation models this can be translated into a measurement of the inflaton coupling in parts of the parameter space. Constraining this microphysical parameter will help to understand how these models of inflation may be embedded into a more fundamental theory of particle physics.

Ricci reheating reloaded

“…Given the capability of future Cosmic Microwave Background experiments to detect a tensorto-scalar ratio at the level of r = O(10 −3 -10 −4 ) while marginally improving the current constraints on the spectral tilt n s [1,3,4], it might become eventually possible to set bounds on the physics of heating [48,49]. Having this in mind, let us make use of the lattice-based relations (3.6) and (3.2) to determine the precise value of the inflationary observables in a specific quintessential-inflation scenario involving only gravitational particle production.…”

Confronting dark matter freeze-in during reheating with constraints from inflation

“…the JCAP01(2024)053 , hence during reheating, RD, and MD, its evolution can differ, as the steepness of the curve reveals. equation of state w rh ≡ w Φ (a < a rh ), the duration of reheating, as well as the reheating temperature [69,70,77]. In figure 8, we show the evolution of the comoving Hubble horizon (aH) −1 in different cosmological epochs.…”

Non-thermal moduli production during preheating in α-attractor inflation models

“…On the other hand, the physics of reheating of producing a thermal bath is still poorly understood. Therefore it is imperative to study post-inflationary physics more carefully to constraint inflation models [30][31][32][33]. In this work, we attempt to constrain α-attractor inflation model demanding that during preheating it does not produce many moduli particles.…”