Threshold corrections to dimension-six proton decay operators in non-minimal SUSY SU(5) GUTs

Abstract We calculate the high and low scale threshold corrections to the D = 6 proton decay mode in supersymmetric S U ( 5 ) grand unified theories with higher-dimensional representation Higgs multiplets. In particular, we focus on a missing-partner model in which the grand unified group is spontaneously broken by the 75 -dimensional Higgs multiplet and the doublet–triplet splitting problem is solved. We find that in the missing-partner model the D = 6 proton decay rate gets suppressed by about 60%, mainly due to the threshold effect at the GUT scale, while the SUSY-scale threshold corrections are found to be less prominent when sfermions are heavy.