Rotating away proton decay in flipped unification

S. M. Barr
2013 Physical Review D  
It is shown that by a simple extension of the fermion sector of flipped SU(5) models and other flipped models proton decay coming from dimension-6 operators can be suppressed by fermion mixing angles by an arbitrary amount in a natural way.
doi:10.1103/physrevd.88.057702 fatcat:xxq2tjjv6rhkrai6jcuknyk77e