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The decay and annihilation cross sections of dark matter particles may depend on the value of a chameleonic scalar field that both evolves cosmologically and takes different values depending on the local matter density. This possibility introduces a separation between the physics relevant for freeze-out and that responsible for dynamics and detection in the late universe. We investigate how such dark sector interactions might be implemented in a particle physics Lagrangian and consider how current and upcoming observations and experiments bound such dark matter candidates. A specific simple model allows for an increase in the annihilation cross section by a factor of 106 between freeze-out and today, while more complicated models should also allow for scattering cross sections near the astrophysical bounds.
Boddy, K. K., Carroll, S. M., & Trodden, M. (2012). Dark Matter with Density-dependent Interactions. Retrieved from https://repository.upenn.edu/physics_papers/272
Date Posted: 31 January 2013
This document has been peer reviewed.