Detectable dimension-6 proton decay in SUSY SO(10) GUT at Hyper-Kamiokande

In the minimal SUSY SU(5) GUT with O(1) TeV SUSY particles and O(1) or below self-coupling for the GUT-breaking Higgs field, the width of the dimension-6 proton decay is suppressed below the reach of Hyper-Kamiokande. In this paper, we point out that a SUSY SO(10) GUT which adopts only 45H+16H+16H GUT-breaking Higgs fields leads to an enhanced dimension-6 proton decay width detectable at Hyper-Kamiokande. The enhancement is because the SU(5)-breaking VEV of 45H arises due to Planck-suppressed terms, W ∝ (45 2H )2/M∗ + 45 4H /M∗, and is therefore substantially larger than the other VEVs that conserve SU(5). As a result, the (3,2, 1/6) GUT gauge boson mass is about 1/5 smaller than the (3,2, −5/6) GUT gauge boson mass and can induce a fast dimension-6 proton decay. Through a numerical analysis on threshold corrections of the GUT gauge bosons and the physical components of the GUT-breaking Higgs fields, we confirm that the dimension-6 proton decay can be within the reach of Hyper-Kamiokande.