Speaker
Description
The type-I Dirac seesaw extension is made to the DFSZ axion model, where light active neutrinos are Dirac particles and acquire mass through the
canonical seesaw mechanism after the Peccei-Quinn and electroweak symmetry breaking, finding that neutrino mass is given by m_{\nu} ≈ 𝑣𝑓{𝑎}/Λ{𝑈𝑉},
result which relates the three energy scales involved in the model: the mass of the heavy sterile Dirac fermions introduced (Λ{𝑈𝑉}), Peccei-Quinn scale
(𝑓{𝑎}), and electroweak scale (𝑣). As a consequence, it was found that 10^(3)*𝑓{𝑎}
~Λ{𝑈𝑉}, hence neutrino Yukawa coupling associated to the QCD axion,
candidate to dark matter, is highly (up to 10^(−10)) suppressed in comparison to the Higgs. Dirac neutrino effective mass matrix is computed explicitly,
whose components depend on active-sterile mixing parameters, the latter being new sources of CP violation. Therefore, the CP asymmetry factor
and the baryon-antibaryon density are computed for the unflavoured leptogenesis, linking neutrino physics, QCD axion, and cosmological
parameters into a same physical framework.
