Search for Anomalous Production of Events with a High Energy Lepton and Photon at the Tevatron

TL;DR

This study searches for anomalous high-energy lepton and photon events at the Tevatron, finding no significant deviations from the Standard Model with a larger dataset and upgraded detector.

Contribution

It provides the first comprehensive analysis with the upgraded CDF II detector and a larger dataset, updating previous results and setting new limits on anomalous event production.

Findings

No significant excess of lepton + photon + MET events.

No observation of rare 'eeggmet' events seen in Run I.

Results are consistent with Standard Model predictions.

Abstract

We present results of a search for for the anomalous production of events containing a high-transverse momentum charged lepton (electron or muon) and photon, accompanied by missing transverse energy (MET), and/or additional leptons and photons, and jets (X). We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305pb-1, a ppbar collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 Lepton + Photon + MET events versus a standard model expectation of 37.3 +- 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 +- 0.7 events (corresponding to a 2.7 sigma effect), is not supported by the new data. In the signature of Multi-Lepton + Photon we observe 31 events versus an expectation of 23.0 +- 2.7 events. In this sample we find no events with an extra photon or MET and so find no events like the one 'two electrons + two photons + MET' ('eeggmet') event observed in Run I.