The Standard Model Partly Supersymmetric
Tony Gherghetta, Alex Pomarol
TL;DR
The Standard Model partly supersymmetric framework addresses naturalness by realizing SUSY only in a bound-state sector described by a 4D CFT, while a separate fundamental sector breaks SUSY at a high scale $\Lambda$ in a slice of AdS$_5$. AdS/CFT interprets the Higgs as a composite bound-state localized on the TeV-brane, with SUSY protection of the Higgs mass parameter and a radiatively generated electroweak scale set by $1/L$, yielding a characteristic little hierarchy relative to $\Lambda$. The Higgs quartic is fixed by SUSY to $\lambda=(g^2+g'^2)/8$, leading to a light Higgs with $m_h\lesssim 120$ GeV, and radiative gauge/top-loop contributions determine $1/L\sim$ TeV with a stop near the TeV scale. Phenomenologically, the model predicts at most one light MSSM-like partner (the Higgsino, and possibly the stop) and a spectrum of TeV-scale, approximately supersymmetric KK resonances, offering distinctive collider signatures and a holographic perspective on SUSY breaking.
Abstract
We present a novel class of theories where supersymmetry is only preserved in a partial (non-isolated) sector. The supersymmetric sector consists of CFT bound-states that can coexist with fundamental states which do not respect supersymmetry. These theories arise from the 4D holographic interpretation of 5D theories in a slice of AdS where supersymmetry is broken on the UV boundary. In particular, we consider the Standard Model where only the Higgs sector (and possibly the top quark) is supersymmetric. The Higgs mass-parameter is then protected by supersymmetry, and consequently the electroweak scale is naturally smaller than the composite Higgs scale. This not only provides a solution to the hierarchy problem, but predicts a ``little'' hierarchy between the electroweak and new physics scale. Remarkably, the model only contains a single supersymmetric partner, the Higgsino (and possibly the stop), and as in the usual MSSM, predicts a light Higgs boson.