# Search for Heavy, Long-Lived Particles that Decay to Photons at CDF II

## TL;DR

This paper reports the first search for heavy, long-lived particles decaying into photons at a hadron collider, using timing and event data from the CDF II detector, setting new mass limits in supersymmetric models.

## Contribution

It introduces a novel search method based on photon arrival times and sets the first experimental limits on certain long-lived supersymmetric particles.

## Key findings

- Observed 2 candidate events consistent with background
- Set the world's best 95% CL lower limit on neutralino mass of 101 GeV/c^2
- Placed constraints on supersymmetric particle properties

## Abstract

We present the first search for heavy, long-lived particles that decay to photons at a hadron collider. We use a sample of photon+jet+missing transverse energy events in p-pbar collisions at \sqrt{s}=1.96 TeV taken with the CDF II detector. Candidate events are selected based on the arrival time of the photon at the detector. Using an integrated luminosity of 570 pb-1 of collision data, we observe 2 events, consistent with the background estimate of 1.3+-0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross section limits in a supersymmetric model with \tilde{\chi}_1^0->\gamma\gravitino and place the world-best 95% C.L. lower limit on the \tilde{\chi}_1^0 mass of 101 GeV/c^2 at \tau_{\tilde{\chi}_1^0} = 5 ns.