Baryo-Leptogenesis induced by modified gravities in the primordial Universe

Understand

The long-standing problem of the asymmetry between matter and antimatter in the Universe is, in this paper, analysed in the context of the modified theories of gravity.

• In particular we study two models of $f(R)$ theories of gravitation that, with the opportune choice of the free parameters, introduce a little perturbation to the scale factor of the Universe in the radiation dominated (RD) phase predicted by general relativity (GR), i.e., $a(t)\sim t^{1/2}$.
• This little perturbation generates a Ricci scalar different by zero, i.e., $R\neq 0$ that reproduces the correct magnitude for the asymmetry factor $\eta$ computed in the frame of the theories of the gravitational baryogenesis and gravitational leptogenesis.
• The opportune choice of the free parameters is discussed in order to obtain results coherent with experimental data.