Flavor-changing axions and Dirac neutrino masses

Abstract

Implementing the axion concept in the context of 3-3-1 extensions of the Standard Model (SM) leads to richer properties than in the simpler axion setups, and related to the Dirac neutrino seesaw mechanism. In this way the smallness of neutrino masses, the strong CP problem, the nature of dark matter and the number of families all have a common origin. Besides having an enhanced coupling to photons, our revamped axion can also be distinguished from DFSZ and KSVZ axions through its couplings to fermions. The latter lead to interesting phenomenological consequences, including flavor-changing axion-emitting two-body K, B and D meson decays.

Figures (7)

• Figure 1: Type-I Dirac seesaw mechanism suppressed by the Peccei-Quinn scale $\left\langle \sigma\right\rangle\equiv v_\sigma$.
• Figure 2: Enhanced axion-to-photon coupling (in GeV$^{-1}$) versus axion mass and decay constant. Our model predictions are compared to those of the KSVZ, DFSZ I and DFSZ II schemes. Current experimental bounds and future projections axionlimaxionpdg are given (black dashed). See text for details.
• Figure 3: Axion-to-electron coupling versus axion mass and decay constant. Our model predictions are compared to those of the KSVZ, DFSZ I and DFSZ II schemes. Current experimental bounds and future projections axionlimaxionpdg are also presented (black dashed). See text for details.
• Figure 4: Axion-to-neutron coupling as function of axion mass (in eV). Our model is compared to KSVZ, DFSZ (both I and II) schemes. Current experimental bounds and future projections (black dashed) axionlimaxionpdg are also indicated.
• Figure 5: Axion-to-proton coupling versus the axion mass (in eV). Our model is compared to KSVZ, DFSZ (both I and II) schemes. Current experimental bounds and future projections (black dashed) axionlimaxionpdg are also indicated.