Searches for heavy long-lived sleptons and R-Hadrons with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports a search for long-lived particles like sleptons and R-hadrons in proton-proton collisions at 7 TeV using the ATLAS detector, setting mass exclusion limits up to nearly 1 TeV.

Contribution

It provides the first set of experimental mass limits on long-lived sleptons and R-hadrons at 7 TeV, based on detailed detector analysis and multiple interaction models.

Findings

No excess of long-lived particles observed.

Excludes long-lived sleptons up to 278 GeV.

Excludes R-hadrons up to 985 GeV.

Abstract

A search for long-lived particles is performed using a data sample of 4.7 fb-1 from proton-proton collisions at a centre-of-mass energy sqrt(s) = 7 TeV collected by the ATLAS detector at the LHC. No excess is observed above the estimated background and lower limits, at 95% confidence level, are set on the mass of the long-lived particles in different scenarios, based on their possible interactions in the inner detector, the calorimeters and the muon spectrometer. Long-lived staus in gauge-mediated SUSY-breaking models are excluded up to a mass of 300 GeV for tan beta = 5-20. Directly produced long-lived sleptons are excluded up to a mass of 278 GeV. R-hadrons, composites of gluino (stop, sbottom) and light quarks, are excluded up to a mass of 985 GeV (683 GeV, 612 GeV) when using a generic interaction model. Additionally two sets of limits on R-hadrons are obtained that are less sensitive to the interaction model for R-hadrons. One set of limits is obtained using only the inner detector and calorimeter observables, and a second set of limits is obtained based on the inner detector alone.