Search for production of resonant states in the photon-jet mass distribution using pp collisions at sqrt(s) = 7 TeV collected by the ATLAS detector

TL;DR

This study conducted a model-independent search for new resonant states in photon-jet events at 7 TeV proton-proton collisions, finding no evidence but setting limits on potential signals and excited-quark models.

Contribution

It provides the first model-independent search for photon-jet resonances at 7 TeV and establishes new exclusion limits on resonance masses and cross sections.

Findings

No significant excess observed over background

Excluded Gaussian resonances at 2 TeV with cross section near 5 fb

Excluded excited-quark (q*) masses below 2.46 TeV

Abstract

This Letter describes a model-independent search for production of new resonant states in photon-jet events in 2.11 fb^-1 of proton-proton collisions at sqrt(s) = 7 TeV. We compare the photon-jet mass distribution to a data-driven background estimate and find consistency with the background hypothesis. Given the lack of evidence for a signal, we set 95% CL limits on generic Gaussian-shape signals and on a benchmark excited-quark (q*) model, excluding 2 TeV Gaussian resonances with cross section times branching ratio times acceptance times efficiency near 5 fb and excluding q* masses below 2.46 TeV, respectively.