Calculable cosmological $CP$ violation and resonant leptogenesis

Within the extension of MSSM by two right-handed neutrinos, with tree level mass degeneracy, we address the issue of leptogenesis. Investigating the quantum corrections in detail, we show that the lepton asymmetry is induced at the one-loop level and a decisive role is played by the tau lepton Yukawa coupling. On a concrete and predictive neutrino model, which enables us to predict the $CP$ violating $\delta$ phase and relate it to the cosmological $CP$ asymmetry, we demonstrate that the needed amount of the baryon asymmetry is generated via the resonant leptogenesis.

Figure 1

Left: Curves for case (I) (see Table 2), with $M=10^4\mathrm{GeV}$, $\delta =+0.378$, $\varphi ={\varphi }_{+}=+1.287$, and with different values of $\tan \beta$. Right: Curves for case (II) (see Table 2), with $\tan \beta =15\mathrm{GeV}$, $\delta =-0.378$, $\varphi ={\varphi }_{+}=-1.287$, and with different values of $M$. Gray horizontal bands correspond to the experimental value of the baryon asymmetry within the $1-\sigma$ range given in Eq. (42).