Search for New Physics in Lepton + Photon + X Events with L=305 pb-1 of ppbar Collisions at roots=1.96 TeV

TL;DR

This study searches for anomalous lepton and photon events in proton-antiproton collisions at 1.96 TeV, finding no significant excess over the standard model predictions with a larger dataset than previous analyses.

Contribution

It provides the first comprehensive search for lepton+photon+X events using 305 pb-1 of data at Tevatron, updating previous results with improved statistics and detector capabilities.

Findings

Observed 42 lepton+photon+MET events vs. 37.3 expected

No significant excess over standard model predictions

No events similar to the Run I ee+gg+MET anomaly

Abstract

We present results of a search for anomalous production of events containing a charged lepton (either electron or muon) and a photon, both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (MET) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb-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+X 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 ee+gg+MET event observed in Run I.