Reheating Effects on Charged Lepton Yukawa Equilibration and Leptogenesis

Abstract

We show that accounting for a non-instantaneous reheating phase after inflation can significantly modify the charged lepton Yukawa equilibration temperature in the early Universe. This finding calls for revisiting the role of lepton flavors in leptogenesis models where right-handed neutrinos are produced and decay during the extended reheating period. Our analysis reveals that this effect can induce shifts in the flavor regime(s) of leptogenesis relative to standard scenario.

Figures (2)

• Figure 1: Variation of $\langle\Gamma_\alpha \rangle/\mathcal{H}$$w.r.t.$$\rm{T}$ for standard (solid lines) and modified (dotted) scenarios. Horizontal dashed line denotes $\langle\Gamma_\alpha \rangle/H=1$, while the vertical dashed lines indicate the ETs of three charged Yukawa interactions.
• Figure 2: Dark brown patch represents the allowed value of RHN mass $M_1$ and coupling $y_\phi^f$ which can produce the correct baryon asymmetry for the scenario with modified flavor regimes. On the contrary, light brown patch represents the allowed region when change in flavor effect was not taken into account. Here $y_\phi^f>3.3\times 10^{-5}$ (in light pink) indicates the nonperturbative regime