Proton Decay at $M_{pl}$ and the Scale of SUSY-Breaking

TL;DR

The paper discusses how the scale of supersymmetry breaking impacts proton decay constraints, showing that higher SUSY scales are needed without flavor structure, but models with flavor symmetry can allow lower scales.

Contribution

It analyzes the relationship between SUSY-breaking scale, flavor structure, and proton decay constraints, highlighting conditions for viable models.

Findings

Higher SUSY scales (~10^{11} GeV) are required without flavor structure.

Flavor symmetry models can satisfy proton decay and flavor constraints at lower SUSY scales.

Suppression of Planck-suppressed proton decay contributions depends on flavor assumptions.

Abstract

It is sometimes argued that a virtue of pushing the supersymmetry breaking scale above 1 PeV is that no particular flavor structure is required in the soft sector in order to evade bounds on flavor-changing neutral currents. However, without flavor structure, suppressing generic Planck-suppressed contributions to proton decay requires even higher SUSY scales, of order $10^{11}$ ($10^9$) GeV for degenerate (mini-split) gauginos and scalars. With flavor structure, the question of whether proton decay or flavor symmetries are more constraining is model-dependent, but it straightforward to find simple models where both constraints are satisfied for much lower SUSY scales.