Baryogenesis from combined Higgs - scalar field inflation

Understand

We study a modification of the Higgs inflation scenario where we introduce an extra scalar $\phi$, with mass $m$, coupled to the Ricci scalar as $g\phi^2 R$, and mixed with the Higgs field $h$ via the Lagrangian term $\mu \phi h^2$.

• Both fields participate in the inflation process in a unitary theory that predicts values of the cosmological observables in agreement with the results from the Planck/BICEP/Keck collaborations.
• In addition, by means of a $\mathcal{CP}$-odd effective operator that couples $\phi$ to the Chern-Simons term of the hypercharge gauge group as $f_\phi^{-1}\phi \,Y_{\mu\nu}\tilde Y^{\mu\nu}$, maximally helical magnetic fields are produced during the last $e$-folds of inflation.
• We found a window in the coupling $ f_\phi$ where these fields survive all constraints until the electroweak phase transition, and source the baryon asymmetry of the Universe through the Standard Model chiral anomaly.