Contorted flavors in grand unification and proton decay

Abstract

Conventionally we collect electron and up/down quarks ( u , d ) ⊕ ( ν e , e ) to form unified generations, and collect the left-handed and the right-handed fermions of the same flavors ( ν e , e ) ⊕ e ¯ . We can alternatively have a contorted multiplet, made by pairing different quarks and leptons, like ( u , d ) ⊕ ( ν μ , μ ) or ( u , d ) ⊕ ( ν τ , τ ) , and/or between different left- and right-handed fermions to ( ν e , e ) ⊕ μ ¯ , etc. These can suppress proton decay, due to its high flavor dependence, while having the correct fermion masses.