Paper detail

Flavour structure of supersymmetric SO(10) GUTs with extended matter sector

We discuss in detail the flavour structure of the supersymmetric SO(10) grand unified models with the three traditional 16-dimensional matter spinors mixed with a set of extra 10-dimensional vector multiplets which can provide the desired sensitivity of the SM matter spectrum to the GUT symmetry breakdown at the renormalizable level. We put the qualitative argument that a successful fit of the quark and lepton data requires an active participation of more than a single vector matter multiplet on a firm, quantitative ground. We find that the strict no-go obtained for the fits of the charged sector observables in case of a single active matter 10 is relaxed if a second vector multiplet is added to the matter sector and excellent, though non-trivial, fits can be devised. Exploiting the unique calculable part of the neutrino mass matrix governed by the SU(2)_L triplet in the 54-dimensional Higgs multiplet, a pair of genuine predictions of the current setting is identified: a non-zero value of the leptonic 1-3 mixing close to the current 90% C.L. limit and a small leptonic Dirac CP phase are strongly preferred by all solutions with the global-fit chi^2-values below 50.