Search for new resonances in $W\gamma$ and $Z\gamma$ Final States in $pp$ Collisions at $\sqrt{s}=8$ TeV with the ATLAS Detector

TL;DR

This paper reports a search for new resonances in $W ext{-}\gamma$ and $Z ext{-}\gamma$ final states in proton-proton collisions at 8 TeV using the ATLAS detector, setting limits on various hypothetical particles with no observed deviations.

Contribution

First search for $V ext{-}\gamma$ resonances at 8 TeV with ATLAS, setting new exclusion limits on technicolor and scalar resonance models.

Findings

Excluded $a_{T}$ and $\omega_{T}$ masses in specified ranges.

Set upper limits on production cross sections for new resonances.

No significant deviations from Standard Model expectations.

Abstract

This letter presents a search for new resonances decaying to final states with a vector boson produced in association with a high transverse momentum photon, $V\gamma$, with $V= W(\rightarrow \ell \nu)$ or $Z(\rightarrow \ell^{+} \ell^{-})$, where $\ell = e$ or $\mu$. The measurements use 20.3 fb$^{-1}$ of proton-proton collision data at a center-of-mass energy of $\sqrt{s}=8$ TeV recorded with the ATLAS detector. No deviations from the Standard Model expectations are found, and production cross section limits are set at 95% confidence level. Masses of the hypothetical $a_{T}$ and $\omega_{T}$ states of a benchmark Low Scale Technicolor model are excluded in the ranges [275,960] GeV and $[200,700]\cup[750,890]$ GeV, respectively. Limits at 95% confidence level on the production cross section of a singlet scalar resonance decaying to $Z\gamma$ final states have also been obtained for masses below 1180 GeV.