Suggested new modes in supersymmetric proton decay

We show that in supersymmetric unified theories such as SO(10), implementation of the see-saw mechanism for neutrino masses introduces a new set of color triplet fields and thereby a new source of d = 5 proton decay operators. For neutrino masses in a plausible range, these operators are found to have the right strength to yield observable, but not yet excluded, proton decay rates. The flavor structure of the new operators is distinctive. Proton decay modes into a charged lepton, such as ℓ⁺ π⁰, ℓ⁺ K⁰ and ℓ⁺ η where ℓ = e or μ, can become prominent, even for low or moderate values of tan β ≤ 10, along with the v̄K⁺ and v̄π⁺ modes. A distinctive feature is the charged lepton modes involving an e⁺ and/or a μ⁺ with the ratio ς(ℓ⁺K⁰):Γ(ℓ+π⁰) ≃ 2:1.