Anatomy of scalar mediated proton decays in SO(10) models

A bstract Realistic models based on the renormalizable grand unified theories have varieties of scalars, many which are capable mediating baryon ( B ) and lepton L number non-conserving processes. We identify all such scalar fields residing in 10 , $$ \overline{\mathbf{126}} 126 ¯ 120 dimensional irreducible representations SO(10) can induce violating interactions through leading order d = 6 7 operators. Explicitly computing their couplings with standard model fermions, we derive effective operators including possibility mixing between scalars stemming from a given representation. find that at mediated by only three sets scalars: T (3 1 −1 / 3), \mathcal{T} T −4 3) \mathbbm{T} 3 conjugates. In first has appropriate to mediate proton decay. While when is present, does not contribute decay tree level because its flavour antisymmetric coupling. Three additional colour triplets conjugates nucleon via violate also − . give general expressions for partial widths terms fundamental Yukawa use these results explicitly compute lifetime branching ratios minimal non-supersymmetric Higgs. preferably decays into \overline{\nu} ν K + or μ 0 list several distinct features If latter dominates over gauge contributions, spectrum provides direct probe structure underlying theory.