First Search for Multijet Resonances in $\sqrt{s} = 1.96$ TeV $ p\bar{p}$ Collisions

TL;DR

This paper reports the first model-independent search for three-jet hadronic resonances in proton-antiproton collisions at 1.96 TeV, setting limits on gluino production without observing a significant signal.

Contribution

It introduces a novel, model-independent analysis method for multijet resonances and provides the first experimental limits on gluino pair production in this context.

Findings

No significant excess observed outside the top quark mass window.

Set 95% confidence level limits on gluino production cross section.

Excluded gluino masses in the range 77 to 240 GeV/c^2.

Abstract

We present the first model independent search for three-jet hadronic resonances within multijet events in $\sqrt{s} = 1.96$ TeV $p\bar{p}$ collisions at the Fermilab Tevatron using the CDF II detector. Pair production of supersymmetric gluinos and squarks with hadronic R-parity violating decays is employed as an example of a new physics benchmark for this signature. Selection criteria based on the kinematic properties of an ensemble of jet combinations within each event help to extract signal from copious QCD background. Our background estimates include all-hadronic $t\bar{t}$ decays that have a signature similar to the signal. No significant excess outside the top quark mass window is observed in data with an integrated luminosity of 3.2 fb$^{-1}$. We place 95% confidence level limits on the production cross section $\sigma(p \bar{p} \rightarrow XX^{'}) \times \rm{BR}$($\widetilde{g}\widetilde{g}$$ \rightarrow 3 {\rm jet}+3 {\rm jet})$ where $X, X' = \widetilde{g}, \widetilde{q}$, or $\widetilde{\bar{q}}$, with $\widetilde{q}$, $\widetilde{\bar{q}} \rightarrow \widetilde{g}$ + jet, as a function of gluino mass, in the range of 77 GeV/$c^2$ to 240 GeV/$c^2$.