Bigravity portal dark matter

Abstract

We consider a model where the interaction between dark matter and the Standard Model particles is mediated by a ghost-free bigravity portal. The bigravity model invokes a massive spin-2 particle coupled to the usual massless graviton as well as generic bimetric matter couplings. The cross sections for dark matter direct detection are computed and confronted with the experimental bounds. The presence of the massive spin-2 mediator resolves the core-cusp problem, which in turn significantly constrains the dark matter coupling in such a bigravity theory. Yet, there remains a window of the parameter space where the model can be tested in the upcoming direct detection experiments such as XENONnT and PandaX-30T. The model also predicts a reheating temperature on the order of 106 GeV. Published by the American Physical Society 2024