Uniting Grand Unified Theory with Brane World Scenario

Uniting Grand Unified Theory with Brane World Scenario We present a field theoretical model unifying grand unified theory (GUT) and brane world scenario.
As a concrete example, we consider SU(5) GUT in 4+1 dimensions where our 3 + 1 dimensional
spacetime spontaneously arises on five domain walls. A field-dependent gauge kinetic
term is used to localize massless non-Abelian gauge fields on the domain walls and to assure
the charge universality of matter fields. We find the domain walls with the symmetry breaking
SU(5) → SU(3) × SU(2) × U(1) as a global minimum and all the undesirable moduli are stabilized
with the mass scale of MGUT. Profiles of massless Standard Model particles are determined as a
consequence of wall dynamics. The proton decay can be exponentially suppressed. VI. CONCLUDING REMARKS: We propose a 4 + 1 dimensional model which unifies
SU(5) GUT and the brane world scenario. Our 3 + 1 dimensional
spacetime dynamically emerges with the symmetry
breaking SU(5) → GSM together with one generation
of the SM matter fields. We solve the gradient
flow equation and confirm the 3-2 splitting configuration
is the global minimum in a large parameter region. By
applying the idea of the field-dependent gauge kinetic
function [24–26] to our model, we solve the long-standing
difficulties of the localization of massless gauge fields and
charge universality. All the undesirable moduli are stabilized.
Furthermore, the proton decay can be exponentially
suppressed.
We have not yet included the SM Higgs field and the
second and higher generations, but our framework can
easily incorporate the former similarly to Ref.[14] and the
latter with the mass hierarchy in the spirit of Ref.[30, 31].
Furthermore, our model can be extended to other GUT
gauge group like SO(10). Supersymmetry and/or warped
spacetime with gravity can also be included without serious
difficulties. Since our model has strong resemblance
to D-branes in superstring theory, we hope that our field theoretical model can give some hints for simple constructions
of SM by D-branes.