Flavor hierarchies from clockwork in SO(10) GUT

The clockwork mechanism, which can naturally explain the origin of small numbers, is implemented in SO(10) grand unified theories to address the origin of hierarchies in fermion masses and mixings. We show that a minimal Yukawa sector involving a 10(H) and (126) over bar (H) of Higgs bosons, extended with two clockwork chains consisting of 16 + (16) over bar vectorlike fermions, can explain the hierarchical patterns with all the Yukawa couplings being of order one. Emergence of a realistic mass spectrum does not require any symmetry that distinguishes the three generations. We develop clockwork-extended SO(10) GUTs both in the context of SUSY and non-SUSY frameworks. Implementation of the mechanism in non-SUSY scenario assumes a Peccei-Quinn symmetry realized at an intermediate scale, with the clockwork sector carrying nontrivial charges, which solves the strong CP problem and provides axion as a dark matter candidate.

Automated summary

The clockwork mechanism is implemented in SO(10) grand unified theories to explain the origin of fermion masses and mixings. No symmetry distinguishing the three generations is required for the mechanism to emerge realistic mass spectrum.