Decoupling heavy sparticles in Effective SUSY scenarios: Unification, Higgs masses and tachyon bounds

TL;DR

This paper investigates Effective SUSY scenarios with decoupled heavy scalars, demonstrating maintained gauge unification, viable Higgs masses around 125 GeV, and relaxed tachyon bounds due to altered RG flow, with implications for sparticle masses.

Contribution

It introduces a two-loop RG analysis with decoupling of heavy scalars, showing improved unification, Higgs mass compatibility, and revised tachyon bounds in Effective SUSY models.

Findings

Gauge coupling unification is preserved or improved.

A 125 GeV Higgs is compatible with ~300 GeV stops/sbottoms under certain conditions.

Tachyon bounds are relaxed by up to a TeV due to modified RG flow.

Abstract

Using two-loop renormalization group equations implementing the decoupling of heavy scalars, Effective SUSY scenarios are studied in the limit in which there is a single low energy Higgs field. Gauge coupling unification is shown to hold with similar or better precision than in standard MSSM scenarios. b-tau unification is examined, and Higgs masses are computed using the effective potential, including two-loop contributions from scalars. A 125 GeV Higgs is compatible with stops/sbottoms at around 300 GeV with non-universal boundary conditions at the scale of the heavy sparticles if some of the trilinear couplings at this scale take values of the order of 1-2 TeV; if more constrained boundary conditions inspired by msugra or gauge mediation are set at a higher scale, heavier colored sparticles are required in general. Finally, since the decoupled RG flow for third-generation scalar masses departs very significantly from the MSSM DR-bar one, tachyon bounds for light scalars are revisited and shown to be relaxed by up to a TeV or more.