A signature-based search for delayed photons in exclusive photon plus missing transverse energy events from $p \bar{p}$ collisions with $\sqrt{s} = 1.96$ TeV

TL;DR

This paper conducts the first search for delayed photons in proton-antiproton collisions, using photon timing to identify potential new physics signals in events with missing transverse energy.

Contribution

It introduces a novel signature-based method for detecting delayed photons in an exclusive photon plus missing energy final state at the Tevatron.

Findings

Observed 322 events compared to 286 ± 24 predicted by background.

Data is consistent with standard model, with a p-value of 12%.

First application of photon timing for delayed photon searches at this energy.

Abstract

We present the first signature-based search for delayed photons using an exclusive photon plus missing transverse energy final state. Events are reconstructed in a data sample from the CDF II detector corresponding to $6.3 \text{fb}^{-1}$ of integrated luminosity from $\sqrt{s}=1.96$ TeV proton-antiproton collisions. Candidate events are selected if they contain a photon with an arrival time in the detector larger than expected from a promptly-produced photon. The mean number of events from standard model sources predicted by the data-driven background model based on the photon timing distribution is $286 \pm 24$. A total of 322 events are observed. A $p$-value of 12% is obtained, showing consistency of the data with standard model predictions.