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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Search for metastable heavy charged particles with large ionization energy loss in pp collisions at √s=13 TeV using the ATLAS experiment
AU - Barton, Adam Edward
AU - Beattie, Michael
AU - Bertram, Iain Alexander
AU - Borissov, Guennadi
AU - Bouhova-Thacker, Evelina Vassileva
AU - Cheatham, Sue
AU - Dearnaley, William
AU - Fox, Harald
AU - Grimm, Kathryn Ann Tschann
AU - Henderson, Robert Charles William
AU - Hughes, Gareth
AU - Jones, Roger William Lewis
AU - Kartvelishvili, Vakhtang
AU - Long, Robin Eamonn
AU - Love, Peter Allan
AU - Muenstermann, Daniel Matthias Alfred
AU - Parker, Adam Jackson
AU - Skinner, Malcolm
AU - Smizanska, Maria
AU - Walder, James William
AU - Wharton, Andy
AU - The ATLAS collaboration
PY - 2016/6/28
Y1 - 2016/6/28
N2 - This paper presents a search for massive charged long-lived particles produced in pp collisions at √s=13 TeV at the LHC using the ATLAS experiment. The data set used corresponds to an integrated luminosity of 3.2 fb−1. Many extensions of the Standard Model predict the existence of massive charged long-lived particles, such as R-hadrons. These massive particles are expected to be produced with a velocity significantly below the speed of light, and therefore to have a specific ionization higher than any Standard Model particle of unit charge at high momenta. The Pixel subsystem of the ATLAS detector is used to measure the ionization energy loss of reconstructed charged particles and to search for such highly ionizing particles. The search presented here has much greater sensitivity than a similar search performed using the ATLAS detector in the √s=8 TeV data set, thanks to the increase in expected signal cross section due to the higher center-of-mass energy of collisions, to an upgraded detector with a new silicon layer close to the interaction point, and to analysis improvements. No significant deviation from Standard Model background expectations is observed, and lifetime-dependent upper limits on R-hadron production cross sections and masses are set. Gluino R-hadrons with lifetimes above 0.4 ns and decaying to qq¯ plus a 100 GeV neutralino are excluded at the 95% confidence level, with lower mass limit ranging between 740 and 1590 GeV. In the case of stable R-hadrons the lower mass limit at the 95% confidence level is 1570 GeV.
AB - This paper presents a search for massive charged long-lived particles produced in pp collisions at √s=13 TeV at the LHC using the ATLAS experiment. The data set used corresponds to an integrated luminosity of 3.2 fb−1. Many extensions of the Standard Model predict the existence of massive charged long-lived particles, such as R-hadrons. These massive particles are expected to be produced with a velocity significantly below the speed of light, and therefore to have a specific ionization higher than any Standard Model particle of unit charge at high momenta. The Pixel subsystem of the ATLAS detector is used to measure the ionization energy loss of reconstructed charged particles and to search for such highly ionizing particles. The search presented here has much greater sensitivity than a similar search performed using the ATLAS detector in the √s=8 TeV data set, thanks to the increase in expected signal cross section due to the higher center-of-mass energy of collisions, to an upgraded detector with a new silicon layer close to the interaction point, and to analysis improvements. No significant deviation from Standard Model background expectations is observed, and lifetime-dependent upper limits on R-hadron production cross sections and masses are set. Gluino R-hadrons with lifetimes above 0.4 ns and decaying to qq¯ plus a 100 GeV neutralino are excluded at the 95% confidence level, with lower mass limit ranging between 740 and 1590 GeV. In the case of stable R-hadrons the lower mass limit at the 95% confidence level is 1570 GeV.
U2 - 10.1103/PhysRevD.93.112015
DO - 10.1103/PhysRevD.93.112015
M3 - Journal article
VL - 93
JO - Physical Review D
JF - Physical Review D
SN - 1550-7998
IS - 11
M1 - 112015
ER -