Searching for Directly Decaying Gluinos at the Tevatron

TL;DR

The paper tackles the gap in gluino searches caused by CMSSM biases by proposing a model-independent jets+$E_T^{\mathrm{miss}}$ framework that scans all kinematically allowed $(m_{\tilde{g}}, m_{\tilde{B}})$ and optimizes $H_T$ and $E_T^{\mathrm{miss}}$ cuts. It employs ISR/FSR-enhanced signal generation with matrix elements for ${\tilde{g}}{\tilde{g}}+Nj$ and MLM matching, then categorizes events into exclusive $n_j+E_T^{\mathrm{miss}}$ channels to maximize $S/\sqrt{S+B}$ under $S/B>1$ and produces 95% CL exclusions across parameter space. The study demonstrates improved sensitivity relative to CMSSM-based searches, especially in the degenerate region and for non-degenerate gluinos, and discusses extensions to cascade decays, bottom-rich final states, squark production, and mono-photon strategies for both Tevatron and LHC. This model-independent approach provides a practical blueprint for future jets+$E_T^{\mathrm{miss}}$ searches at hadron colliders, with broad applicability to beyond-Standard-Model scenarios involving color octets.

Abstract

This letter describes how to perform searches over the complete kinematically-allowed parameter space for new pair-produced color octet particles that each subsequently decay into two jets plus missing energy at the Tevatron. This letter shows that current searches can miss otherwise discoverable spectra of particles due to CMSSM-motivated cuts. Optimizing the HT and MET cuts expands the sensitivity of these searches.

Figures (2)

• Figure 1: Boosted gluinos that are degenerate with the bino do not enhance the missing transverse energy when there is no hard initial- or final-state radiation. (A) illustrates the cancellation of the bino's $\hbox{$E_T\space\not\space$}$. (B) shows how initial- or final-state radiation leads to a large amount of $\hbox{$E_T\space\not\space$}$ even if the gluino is degenerate with the bino.
• Figure 2: The 95% gluino-bino exclusion curve for ${\hbox{DO $\not$}}$ at 4 fb$^{-1}$ for $S/B >1$. The dashed line shows the corresponding exclusion region using ${\hbox{DO $\not$}}$'s non-optimized cuts. The masses allowed in the CMSSM are represented by the dotted line; the "X" marks the current ${\hbox{DO $\not$}}$ limit on the gluino mass at 2.1 fb$^{-1}$ (see text for details) Abazov:2007ww. The inset shows the effect of scaling the production cross section for the case of $S/B>1$. The solid lines show the exclusion region for $\sigma/3$ (bottom) and $3\sigma$ (top).