Rates of particle production in $R^2$ gravity and supersymmetry-kind dark matter

Universe heating in $R^2$-modified gravity is considered. The rates of particle production by the scalaron are calculated for different decay channels. Freezing of massive stable relics with the interaction strength typical for supersymmetry is studied. It is shown that the bounds on masses of supersymmetry-kind particles allowing them to form the cosmological dark matter (DM)depend upon the dominant decay mode of the scalaron. In any case the results presented open much wider mass window for DM with the interaction strength typical for supersymmetry.
Comment: 21 pages, 4 figures, 1 table. Extended version of the invited talk presented at International Workshop on Elementary Particles and Nuclear Physics, 24 -- 30 April 2022, Institute of Nuclear Physics of the Ministry of Energy of the Republic of Kazakhstan, Almaty