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Title: Search for metastable heavy charged particles with large ionisation energy loss in pp collisions at $${\sqrt{s} = 8}$$ s = 8 TeV using the ATLAS experiment

Many extensions of the Standard Model predict the existence of charged heavy long-lived particles, such as R-hadrons or charginos. These particles, if produced at the Large Hadron Collider, should be moving non-relativistically and are therefore identifiable through the measurement of an anomalously large specific energy loss in the ATLAS pixel detector. Measuring heavy long-lived particles through their track parameters in the vicinity of the interaction vertex provides sensitivity to metastable particles with lifetimes from 0.6 ns to 30 ns. A search for such particles with the ATLAS detector at the Large Hadron Collider is presented, based on a data sample corresponding to an integrated luminosity of \(18.4\) fb\(^{-1}\) of pp collisions at \(\sqrt{s} = 8\) TeV. No significant deviation from the Standard Model background expectation is observed, and lifetime-dependent upper limits on R-hadrons and chargino production are set. Gluino R-hadrons with 10 ns lifetime and masses up to 1185 GeV are excluded at 95 \(\%\) confidence level, and so are charginos with 15 ns lifetime and masses up to 482 GeV.
  1. National Centre for Scientific Research (CNRS), Marseilles (France). Centre for Particle Physics of Marseilles (CPPM); et al.
Publication Date:
OSTI Identifier:
Grant/Contract Number:
AC03-76SF00515; AC02-06CH11357; AC02-05CH11231; SC00112704; AC02-98CH10886; AC02-76CH00016; SC0012704; AC03-76SF00098
Accepted Manuscript
Journal Name:
European Physical Journal. C, Particles and Fields
Additional Journal Information:
Journal Volume: 75; Journal Issue: 9; Journal ID: ISSN 1434-6044
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Contributing Orgs:
ATLAS Collaboration
Country of Publication:
United States