MSGUTS: from germ to bloom - towards falsifiability and beyond

by Charanjit S. Aulakh (Panjab University, Chandigarh)

Friday 24 Jun 2005, 14:00 → 15:00 Europe/Zurich

TH Auditorium (CERN)

We review the development of the renormalizable SO(10) SUSY GUTs based on the 210 ⊕ 126 ⊕ {overline {126}} Higgs system which are minimal by parameter counting. Using a $SO(10) -> G_Pati-Salam label decomposition we calculate the complete GUT scale spectra and couplings. This is used to compute the threshold effects on the gauge renormalization. These corrections to Δα_G, Δs_w2, Δ log M_X are sensitive functions of the single parameter Δ that controls the cubic symmetry-breaking equation in this MSGUT and slow functions of the 4 other coupling parameters. Thus a scan of the solution space to restrict it to viable gauge regions is possible. We review the recent successful 10 ⊕ {overline {126}} Type I and Type II fits of all fermion mass/mixing data and show how they specify the unitary matrices that enter into the definition of the exotic (ΔB≠ 0) effective Lagrangian at the GUT scale. This puts semi-rigorous calculation of proton decay in this theory within reach. We show how these fits can be com-bined with our GUT spectra to further severely constrain the MSGUT and the mass/mixing fits referred to. Similar techniques can be applied to the next-to-minimal MSGUT which in addition contains a 120-plet. Thus we have moved within reach of specifying the MSGUT fitted to low-energy data to a precision that will make it falsifiable. The remnant regions of its parameter space - if any - will then await further refinement by (non) observation of exotic processes.