Scalar-tensor Baryogenesis

Abstract: We propose a baryogenesis mechanism termed scalar-tensor baryogenesis, analogous to gravitational and spontaneous baryogenesis, driven by scalar fields arising from the scalar-tensor representation of modified gravity theories. This mechanism reproduces the original interaction term of gravitational baryogenesis and those commonly introduced in modified gravity contexts. We demonstrate the mechanism within $f(R,T)$ and $f(R)$ gravity frameworks, focusing on $f(R)$. We explore a quintessence potential given by $V(\phi) = \alpha \frac{\phi^{m+1}}{{m+1}}$ and a potential given $V(\phi) = \beta^{-\frac{1}{n-1}}(n-1)\left(\frac{\phi - 1}{n}\right)^{\frac{n}{n-1}}$ that corresponds in the geometric representation to models of the form $R + \beta R^n$. The model with $n=2$ presented the best behavior in generating an acceptable asymmetry during the radiation-dominated epoch. Inspired by this result, employing Planck data, we explored the Starobinsky inflation model obtaining successful baryogenesis during the inflationary epoch for both gravitational and scalar-tensor baryogenesis.