Stealth Supersymmetry

TL;DR

Stealth SUSY introduces a hidden, weak-scale sector with nearly degenerate supermultiplets that suppress missing energy while preserving R-parity. By exploiting low-scale SUSY breaking and approximate supersymmetry in the hidden sector, the framework yields tiny $\delta m$ splittings and soft gravitinos, producing jet-rich cascades with false resonances rather than MET. The paper develops two minimal realizations, $\mathbf{S H_u H_d}$ and $\mathbf{S Y\bar{Y}}$, and analyzes 2-body versus 3-body decays, MET implications, and several discovery channels such as displaced vertices and $\gamma j j$ resonances, including a false-resonance program to reconstruct hidden-sector masses. This approach provides a natural, gauge-unified alternative to conventional SUSY signatures and motivates dedicated experimental searches beyond MET-based strategies.

Abstract

We present a broad class of supersymmetric models that preserve R-parity but lack missing energy signatures. These models have new light particles with weak-scale supersymmetric masses that feel SUSY breaking only through couplings to the MSSM. This small SUSY breaking leads to nearly degenerate fermion/boson pairs, with small mass splittings and hence small phase space for decays carrying away invisible energy. The simplest scenario has low-scale SUSY breaking, with missing energy only from soft gravitinos. This scenario is natural, lacks artificial tunings to produce a squeezed spectrum, and is consistent with gauge coupling unification. The resulting collider signals will be jet-rich events containing false resonances that could resemble signatures of R-parity violation. We discuss several concrete examples of the general idea, and emphasize gamma + jet + jet resonances, displaced vertices, and very large numbers of b-jets as three possible discovery modes.

Figures (4)

• Figure 1: An example spectrum and decay chain for Stealth SUSY with gluino LVSP.
• Figure 2: Three-body decays $\tilde{X} \to \tilde{G}X^*(\to j j)$ can become important if $\delta m$ is small and $\Gamma_X$ is not too small. The solid line is for $X$ decaying through a Yukawa coupling, whereas the dashed line is for $X$ decaying to gauge bosons.
• Figure 3: At left: Missing transverse energy (MET) in a SUSY scenario with gluino decaying to bino ($\tilde{g} \to q\bar{q}\tilde{\chi}^0_1$) compared to a decay chain $\tilde{g} \to g(\tilde{s}\to \tilde{G}(s\to gg))$ as in Fig. \ref{['fig:schema']}. The curves are labeled by mass splitting. At right: estimated exclusion contours using refs. LHCjetsmet. The region above the curves is excluded. The curves are labeled by singlino mass and begin where $m_{\tilde{g}} > m_{\tilde{s}}$.
• Figure 4: Red, solid: $M(\gamma j j)$ for all triplets passing a cut on mass relative to $\sum p_T$. Note the peak at the bino mass of 300 GeV and the falling feature near the squark mass of 500 GeV. Green, dashed: $M(\gamma j j)$ for jet pairs tagged as an $s$ decay via vertexing, together with each photon (no cut on $\sum p_T$ is applied).