Superheavy dark matter in $$R+R^2$$ cosmology with conformal anomaly

Abstract

Cosmological evolution and particle creation in $$R^2$$ R 2 -modified gravity are considered for the case of the dominant decay of the scalaron into a pair of gauge bosons due to conformal anomaly. It is shown that in the process of thermalization superheavy dark matter with the coupling strength typical for the GUT SUSY can be created. Such dark matter would have the proper cosmological density if the particle mass is close to $$10^{12}$$ 10 12 GeV.

R2-Cosmology and New Windows for Superheavy Dark Matter

“…The direct decay can be very strongly suppressed if X-particles are Majorana fermions, which cannot be created by a scalar field in the lowest order of perturbation theory. This opens the possibility for X-particles to make proper amount of dark matter, if their mass is about 5 × 10 12 GeV [38].…”

“…According to results of our papers [23,38,44] the mass of dark matter particles, with the interaction strength typical for supersymmetric ones, can be in the range from 10 6 to the value exceeding the scalaron mass, M R = 10 13 GeV. It is tempting to find if and how they could be observed, except for their gravitational effects on galactic and cosmological scales.…”

“…Following our paper [38] we present alternative, more rigorous arguments leading to introduction of canonically normalised field Φ (110). To this end we rewrite the first term of action (51) in the Jordan frame in the high frequency limit in terms of the cosmological scale factor a(t) in the way analogous to the derivation of the Friedmann equations performed in Ref.…”

New Options for SUSY-kind Dark Matter

“…If the scalaron decay is induced by the conformal anomaly, the decay width of the scalaron and the energy density of the produced gauge bosons will be correspondingly [5]:…”