Scalaron dark matter and the thermal history of the universe

Abstract

In metric $f(R)$ gravity minimally coupled to the Standard Model, the scalaron field can act as a dark-matter candidate if its mass lies in the range $\text{meV}\lesssim m\lesssim \text{MeV}$. The evolution of the scalaron is influenced by the trace of the stress-energy tensor, whose behaviour, as shown in our previous work, becomes non-adiabatic during the electroweak crossover, potentially triggering scalaron oscillations. While we previously approximated this crossover as a second-order phase transition at the one-loop level, the transition is actually smoother. In this paper, we refine our analysis to account for this smooth crossover and show that scalaron oscillations are still excited in a qualitatively similar manner, driven by the rapid dynamics of the electroweak crossover observed in numerical lattice simulations, provided the scalaron mass is sufficiently small. We also investigate the time-dependent contribution to the stress-energy trace due to the trace anomaly of quantum chromodynamics. Our results indicate that, while the trace anomaly shifts the scalaron's equilibrium value, this shift evolves adiabatically compared to the fast oscillations of the scalaron, meaning that the trace anomaly does not significantly affect the potential cosmological scenarios for scalaron evolution.

arXiv comment17 pages, 1 figure, substantially revised and extended version accepted for publication in JCAP

References in corpus (42)

• f(R) Theories Of Gravity
• f(R) theories
• Towards the Theory of Reheating After Inflation
• Reheating after Inflation
• Chameleon Fields: Awaiting Surprises for Tests of Gravity in Space
• Chameleon Cosmology
• The equation of state in (2+1)-flavor QCD
• Full result for the QCD equation of state with 2+1 flavors
• Thermodynamics of SU(3) Lattice Gauge Theory
• Tests of the Gravitational Inverse-Square Law below the Dark-Energy Length Scale
• Universe Reheating after Inflation
• Is There a Hot Electroweak Phase Transition at $m_H\gsim m_W$?
• Particle Physics Implications of a Recent Test of the Gravitational Inverse Square Law
• Tests of Chameleon Gravity
• f(R) Gravity and Chameleon Theories
• Dark energy and dark matter as curvature effects
• Magnetic fields from inflation?
• The Standard Model cross-over on the lattice
• Dark Matter from R^2-gravity
• Where the electroweak phase transition ends
• Review of short-range gravity experiments in the LHC era
• Standard Model thermodynamics across the electroweak crossover
• The Electrical Conductivity in the Early Universe
• What's new with the electroweak phase transition?
• Gravitational Waves in $F(R)$ Gravity: Scalar Waves and the Chameleon Mechanism
• Modified Gravity Explains Dark Matter?
• Hints of Modified Gravity in Cosmos and in the Lab?
• Cosmic History of Chameleonic Dark Matter in $F(R)$ Gravity
• Dark matter as scalaron in $f(R)$ gravity models
• Four-dimensional Simulation of the Hot Electroweak Phase Transition with the SU(2) Gauge-Higgs Model
• Scalarons mimicking Dark Matter in the Hu-Sawicki model of f(R) gravity
• High-energy scalarons in R^{2} gravity as a model for Dark Matter in galaxies
• Light scalaron as dark matter
• Model-independent constraints in inflationary magnetogenesis
• Modified gravity and dark matter
• Unified $f(R)$ gravity at local scales
• Origin of the Proton Mass
• Post-inflationary preheating with weak coupling
• Initial conditions for the scalaron dark matter
• Revisiting compact star in $F(R)$ gravity: Roles of chameleon potential and energy conditions
• $F(R)$ gravity in the early Universe: Electroweak phase transition and chameleon mechanism
• On the Conformal Frames in $f(R)$ Gravity

Cited by in corpus (3)

• Interactions of the scalaron dark matter in $f(R)$ gravity
• Effective scalaron--photon interaction in $f(R)$ gravity
• Theoretical and observational constraints on early dark energy in $F(R)$ gravity