Particle Production in f(R) Gravity during Structure Formation

Understand

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.