  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".

High Energy Physics - Phenomenology;High Energy Physics - Experiment