Search for a heavy particle decaying into an electron and a muon with the ATLAS detector in sqrt(s) = 7 TeV pp collisions at the LHC

TL;DR

This paper reports the first search for a heavy particle decaying into an electron-muon final state at the LHC, setting new exclusion limits on certain supersymmetric and Z'-like models based on 2010 data.

Contribution

It introduces the first search for eμ decays of heavy particles at 7 TeV LHC and sets new exclusion limits on R-parity violating sneutrinos and lepton flavor violating Z' bosons.

Findings

No excess observed above Standard Model background.

Excluded tau sneutrinos below 0.75 TeV in specific SUSY models.

Excluded Z'-like bosons between 0.70 and 1.00 TeV.

Abstract

This Letter presents the first search for a heavy particle decaying into an e\mu final state in sqrt(s)=7 TeV pp collisions at the LHC. The data were recorded by the ATLAS detector during 2010 and correspond to a total integrated luminosity of 35/pb. No excess above the Standard Model background expectation is observed. Exclusions at 95% confidence level are placed on two representative models. In an R-parity violating supersymmetric model, tau sneutrinos with a mass below 0.75 TeV are excluded, assuming single coupling dominance and the couplings lambda'_{311}=0.11, lambda_{312}=0.07. In a lepton flavor violating model, a Z'-like vector boson with masses of 0.70 to 1.00 TeV and corresponding cross sections times branching ratios of 0.175 to 0.183 pb is excluded. These results extend to higher mass RPV sneutrinos and LFV Z's than previous constraints from the Tevatron.