Particle Production in f(R) Gravity during Structure Formation

TL;DR

This paper investigates how oscillations in the curvature scalar in f(R) gravity models during structure formation can produce particles efficiently, potentially explaining cosmic rays and constraining modified gravity theories.

Contribution

It demonstrates that high-frequency curvature oscillations in f(R) gravity can lead to significant particle production, offering a new perspective on cosmic ray origins and model viability.

Findings

Oscillations cause efficient particle production.

Potential explanation for energetic cosmic rays.

Constraints on certain f(R) gravity models.

Abstract

We study particle production in infrared-modified gravitational theories in the contemporary universe. It is shown that in astronomical systems with rising mass density, the curvature scalar may oscillate with very high frequency. These oscillations lead to efficient particle production and in an interesting range of model parameters could be a source of energetic cosmic rays. This effect either excludes some models of modified gravity or suggests a new mechanism of cosmic ray production.