Search for contact interactions in dilepton events from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper searches for contact interactions in dilepton events at 7 TeV proton-proton collisions using ATLAS data, setting new lower limits on the energy scale of potential new physics beyond the standard model.

Contribution

It provides the first limits on contact interactions in dilepton channels at 7 TeV using ATLAS data, employing a Bayesian approach with different priors.

Findings

No significant deviations from the standard model observed.

Lower limits on contact interaction scale set at 10.1 TeV and 9.4 TeV for electrons.

Lower limits on contact interaction scale set at 8.0 TeV and 7.0 TeV for muons.

Abstract

This Letter presents a search for contact interactions in the dielectron and dimuon channels using data from proton-proton collisions produced by the LHC at sqrt(s) = 7 TeV and recorded by the ATLAS detector. The data sample, collected in 2011, corresponds to an integrated luminosity of 1.08 and 1.21 fb^-1 in the e+ e- and mu+ mu- channels, respectively. No significant deviations from the standard model are observed. Using a Bayesian approach with a prior flat in 1/Lambda^2, the following 95% CL lower limits are placed on the energy scale of llqq contact interactions: Lambda^- > 10.1 TeV (Lambda^+ > 9.4 TeV) in the electron channel and Lambda^- > 8.0 TeV (Lambda^+ > 7.0 TeV) in the muon channel for constructive (destructive) interference in the left-left isoscalar contact interaction model. Limits are also provided for a prior flat in 1/Lambda^4.