Clark, Brian LeeFranklin, MelissaHuth, JohnIppolito, ValerioLazovich, TomoLopez Mateos, DavidMercurio, KevinMorii, MasahiroSpearman, WilliamSun, SiyuanTolley, EmmaYen, Andy2017-09-062015Aad, G., B. Abbott, J. Abdallah, O. Abdinov, R. Aben, M. Abolins, et al. 2015. “Search for metastable heavy charged particles with large ionisation energy loss in pp collisions at √s= 8 TeV using the ATLAS experiment.” The European Physical Journal C 75 (9) (September). doi:10.1140/epjc/s10052-015-3609-0.1434-6044http://nrs.harvard.edu/urn-3:HUL.InstRepos:33839902Many 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 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.en-USJournal Article2017-09-0610.1140/epjc/s10052-015-3609-0