Search for Long-Lived Massive Charged Particles in 1.96 TeV $\bar{p}p}$ Collisions

TL;DR

This study conducted a search for long-lived charged massive particles in proton-antiproton collisions at 1.96 TeV, using time-of-flight measurements to identify slowly moving particles, resulting in setting mass limits on certain theoretical particles.

Contribution

It presents the first search for long-lived charged particles at this energy with time-of-flight, establishing new mass bounds within the scalar top quark model.

Findings

One candidate event observed with expected background of 1.9 events.

Set a lower mass limit of 249 GeV/c^2 for stable scalar top quarks.

No significant excess indicating discovery was found.

Abstract

We performed a signature-based search for long-lived charged massive particles (CHAMPs) produced in 1.0 $\rm{fb}^{-1}$ of $\bar{p}p$ collisions at $\sqrt{s}=1.96$ TeV, collected with the CDF II detector using a high transverse-momentum ($p_T$) muon trigger. The search used time-of-flight to isolate slowly moving, high-$p_T$ particles. One event passed our selection cuts with an expected background of $1.9 \pm 0.2$ events. We set an upper bound on the production cross section, and, interpreting this result within the context of a stable scalar top quark model, set a lower limit on the particle mass of 249 GeV/$c^2$ at 95% C.L.