Search for Supersymmetry with Gauge-Mediated Breaking in Diphoton Events with Missing Transverse Energy at CDF II

TL;DR

This study searches for supersymmetry with gauge-mediated breaking in diphoton events with missing energy at CDF II, finding no candidate events and setting new limits on particle masses and lifetimes.

Contribution

First to set experimental limits on gauge-mediated supersymmetry breaking parameters using diphoton plus missing energy data at CDF II.

Findings

No candidate events observed, consistent with background.

Set a 95% CL limit of 149 GeV/c^2 on the neutralino mass.

Excluded neutralino masses and lifetimes in specific regions.

Abstract

We present the results of a search for supersymmetry with gauge-mediated breaking and $\NONE\to\gamma\Gravitino$ in the $\gamma\gamma$+missing transverse energy final state. In 2.6$\pm$0.2 \invfb of $p{\bar p}$ collisions at $\sqrt{s}$$=$1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4$\pm$0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149\gevc on the \none mass at $\tau_{\tilde{\chi}_1^0}$$<<$1 ns. We also exclude regions in the \none\ mass-lifetime plane for $\tau_{\tilde{\chi}_1^0}$$\lesssim$2 ns.