SU(5) orbifold GUT in noncommutative geometry

Abstract

In this paper, we appliy the orbifold GUT mechanism to the SU(5) model in noncommutative geometry, including the fermonic sector. Imposing proper parity assignments for "constituent fields" of bosons and fermions, the couplings between fermions and the heavy bosons $X_{\mu },Y_{\mu }$, and $H^c$ are prohibited by the parity symmetry. As a result, the derived fermionic Lagrangian is just that of the standard model, and proton decay is forbidden at tree level. If quantum fluctuation respects the parity symmetry, the process will be naturally suppressed or even forbidden completely.

Comments: 13 pages, the final version to appear in Progress of Theoretical and Experimental Physics (PTEP)