Sleptonic SUSY: From UV Framework to IR Phenomenology

TL;DR

This paper explores a specific SUSY scenario called Sleptonic SUSY, which addresses Higgs mass, dark matter, and muon g-2 anomalies through a hierarchical spectrum and novel UV mechanisms, with implications for collider and dark matter experiments.

Contribution

It introduces a UV framework for Sleptonic SUSY using higher-dimensional sequestering and gaugino-mediation, solving flavor, CP, and μ problems, and extends to orbifold GUTs and non-minimal Higgs models.

Findings

Viable sleptonic spectra with sub-TeV sleptons and electroweakinos.

Rich collider signals including R-parity conserving and violating scenarios.

Potential explanations for the muon g-2 anomaly and dark matter detection prospects.

Abstract

We study an attractive scenario, "Sleptonic SUSY", which reconciles the $125$ GeV Higgs scalar and the non-observation of superpartners thus far with potentially pivotal roles for slepton phenomenology: providing viable ongoing targets for LHC discovery, incorporating a co-annihilation partner for detectable thermal relic dark matter, and capable of mediating the potential muon $g-2$ anomaly. This is accomplished by a modestly hierarchical spectrum, with sub-TeV sleptons and electroweakinos and with multi-TeV masses for the other new states. We study new elements in the UV MSSM realization of Sleptonic SUSY based on higher-dimensional sequestering and the synergy between the resulting gaugino-mediation, hypercharge $D$-term mediation and Higgs-mediation of SUSY-breaking, so as to more fully capture the range of possibilities. This framework stands out by harmoniously solving the flavor, CP and $\mu - B\mu$ problems of the supersymmetric paradigm. We discuss its extension to orbifold GUTs, including gauge-coupling and $b$-tau unification. We also develop a non-minimal model with extra Higgs fields, in which the electroweak vacuum is more readily cosmologically stable against decay to a charge-breaking vacuum, allowing a broader range of sleptonic spectra than in the MSSM alone. We survey the rich set of signals possible at the LHC and future colliders, covering both $R$-parity conservation and violation, as well as for dark matter detection. While the multi-TeV squarks imply a Little Hierarchy Problem, intriguingly, small changes in parameter space to improve naturalness result in dramatic phase transitions to either electroweak-preservation or charge-breaking. In a Multiverse setting, the modest unnaturalness may then be explained by the "principle of living dangerously".