Unifying Inflation with the Axion, Dark Matter, Baryogenesis, and the Seesaw Mechanism

Area of Science:

• Particle Physics
• Cosmology
• Astroparticle Physics

Background:

• The Standard Model (SM) is incomplete, lacking explanations for dark matter, neutrino masses, and the strong CP problem.
• Existing extensions often require multiple new scales or introduce complexities not supported by current data.

Purpose of the Study:

• To present a minimal extension of the SM that unifies particle physics and cosmology up to the Planck scale.
• To provide a consistent theoretical framework for inflation, baryogenesis, dark matter, and neutrino masses.
• To introduce a mechanism for breaking lepton number and Peccei-Quinn symmetry simultaneously.

Main Methods:

• Extension of the SM with three right-handed neutrinos, a vectorlike color triplet fermion, and a complex scalar sigma.
• Utilizing the scalar sigma and SM Higgs for primordial inflation via nonminimal coupling.
• Employing thermal leptogenesis for baryogenesis.
• Incorporating seesaw mechanism for neutrino masses and an axion for the strong CP problem and dark matter.

Main Results:

• The model successfully unifies inflation, baryogenesis, neutrino masses, and dark matter within a single framework.
• Predicts specific values for cosmological parameters: tensor-to-scalar ratio (r) of at least 0.004 and scalar spectral index running (α) of approximately -7x10^-4.
• Predicts an axion mass of ~100 μeV and a cosmic axion background radiation impacting the effective number of relativistic neutrinos.

Conclusions:

• The proposed minimal extension offers a compelling and consistent picture of fundamental physics and cosmology.
• The model's predictions are testable with next-generation cosmic microwave background and axion dark matter experiments.
• This framework provides a unified solution to several outstanding problems in particle physics and cosmology.