Search for new phenomena in events with a photon and missing transverse momentum in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

TL;DR

This paper reports a search for new physics phenomena involving photons and missing transverse momentum in proton-proton collisions at 8 TeV, finding results consistent with the Standard Model and setting limits on various beyond Standard Model theories.

Contribution

First search for photon plus missing energy events at 8 TeV with ATLAS, providing new exclusion limits on extra dimensions, supersymmetry, and dark matter models.

Findings

Observed data matches Standard Model predictions.

Set upper limits on production cross sections for new phenomena.

Excluded certain parameter spaces in extra dimensions, SUSY, and dark matter models.

Abstract

Results of a search for new phenomena in events with an energetic photon and large missing transverse momentum with the ATLAS experiment at the LHC are reported. Data were collected in proton--proton collisions at a center-of-mass energy of 8 TeV and correspond to an integrated luminosity of 20.3 fb$^{-1}$. The observed data are well described by the expected Standard Model backgrounds. The expected (observed) upper limit on the fiducial cross section for the production of such events is 6.1 (5.3) fb at 95% confidence level. Exclusion limits are presented on models of new phenomena with large extra spatial dimensions, supersymmetric quarks, and direct pair production of dark-matter candidates.