Tevatron Signatures of Long-lived Charged Sleptons in Gauge-Mediated Supersymmetry Breaking Models

TL;DR

The paper analyzes gauge-mediated SUSY breaking scenarios with a long-lived charged stau NLSP, exploring distinctive collider signatures such as highly ionizing tracks, dimuon-like excesses, and high-multiplicity lepton events. By adopting a calculable GM model with messenger content $N_5$, it derives the SUSY spectrum and production channels, then estimates Tevatron discovery prospects for direct slepton production, gaugino cascades, and mixed signatures across Run I and projected Run II/TeV33 luminosities. It translates signal reach into physical masses and into the fundamental $(M,\Lambda)$ parameter space, highlighting that Tevatron Run I probes regions beyond LEP bounds and that future runs can access substantial portions of typical GM parameter space, especially via gaugino and multi-lepton channels. The study emphasizes that signatures from long-lived charged sleptons are powerful, largely background-free probes of GM physics with significant implications for collider searches.

Abstract

In supersymmetric models with gauge-mediated supersymmetry breaking, charged sleptons are the next lightest supersymmetric particles and decay outside the detector for large regions of parameter space. In such scenarios, supersymmetry may be discovered by searches for a number of novel signals, including highly ionizing tracks from long-lived slow charged particles and excesses of multi-lepton signals. We consider this scenario in detail and find that the currently available Tevatron data probes regions of parameter space beyond the kinematic reach of LEP II. Future Tevatron runs with integrated luminosities of 2, 10, and 30 fb-1 probe right-handed slepton masses of 110, 180, and 230 GeV and Wino masses of 310, 370, and 420 GeV, respectively, greatly extending current search limits.

Figures (15)

• Figure 1: Contours of $M_{\tilde{\tau}_R}(M_{\text{MSSM}}) = M_1(M_{\text{MSSM}})$ for $M_{\text{MSSM}}=1\text{ TeV}$ and $\tan\beta = 3$, 10, and 30. In the region above the contours, $\tilde{\tau}_1$ is the NLSP; in the region below, $\chi^0_1$ is the NLSP. In the shaded region, gauge coupling constants become non-perturbative below the GUT scale under two-loop RG evolution.
• Figure 2: Contours of the ratio of soft SUSY breaking parameters $M_{\tilde{\tau}_R}(M_{\text{MSSM}})/M_1(M_{\text{MSSM}})$ for $\tan\beta=3$ and $M_{\text{MSSM}}=1\text{ TeV}$. In the lower shaded region, $M_{\tilde{\tau}_R}(M_{\text{MSSM}}) > M_1(M_{\text{MSSM}})$. In the upper shaded region, gauge coupling constants become non-perturbative below the GUT scale.
• Figure 3: Contours of the ratio of soft SUSY breaking parameters $M_{\tilde{l}_L}(M_{\text{MSSM}})/M_2(M_{\text{MSSM}})$ for $\tan\beta=3$ and $M_{\text{MSSM}}=1\text{ TeV}$. In the lower shaded region, $M_{\tilde{\tau}_R}(M_{\text{MSSM}}) > M_1(M_{\text{MSSM}})$. In the upper shaded region, gauge coupling constants become non-perturbative below the GUT scale.
• Figure 4: Cross sections for $p\bar{p} \to \gamma^*, Z^* \to \tilde{\tau}_1 \tilde{\tau}_1^*$ for $\sqrt{s} = 1.8$ TeV (lower) and 2 TeV (upper), and $\tilde{\tau}_1 \approx \tilde{\tau}_R$.
• Figure 5: Cross sections for the production of at least one slow $\tilde{\tau}_1$ from $p\bar{p} \to \gamma^*, Z^* \to \tilde{\tau}_1 \tilde{\tau}_1^*$ at $\sqrt{s} = 2 \text{ TeV}$, where we have required $|\eta|\leq 0.6$ for the slow $\tilde{\tau}_1$. Contours correspond to $\beta\gamma\leq 0.4$ (dotted), 0.7 (dashed), 0.85 (solid), and $\infty$ (dot-dashed).