Search for anomalous production of prompt same-sign lepton pairs and pair-produced doubly charged Higgs bosons with $\sqrt{s} = 8$ TeV $pp$ collisions using the ATLAS detector

TL;DR

This paper reports a search for new physics involving same-sign dilepton pairs using 8 TeV proton-proton collision data from the ATLAS detector, finding no excess and setting limits on beyond Standard Model processes.

Contribution

First search for anomalous same-sign dilepton production at 8 TeV with ATLAS, setting limits on doubly charged Higgs bosons and other new physics models.

Findings

No excess events observed over Standard Model background.

Upper limits set on cross-sections for new physics processes.

Exclusion limits derived for doubly charged Higgs boson production.

Abstract

A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses proton-proton collisions corresponding to 20.3 fb$^{-1}$ of integrated luminosity taken in 2012 at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. Pairs of isolated leptons with the same electric charge and large transverse momenta of the type $e^{\pm}e^{\pm}, e^{\pm}\mu^{\pm}$, and $\mu^{\pm}\mu^{\pm}$ are selected and their invariant mass distribution is examined. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the cross-sections for processes beyond the Standard Model. Limits are placed as a function of the dilepton invariant mass within a fiducial region corresponding to the signal event selection criteria. Exclusion limits are also derived for a specific model of doubly charged Higgs boson production.