A search for supersymmetry through the direct pair production of top squarks, with Higgs (H) or Z bosons in the decay chain, is performed using a data sample of proton–proton collisions at sqrt(s) = 8 TeV collected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 fb^{-1}. The search is performed using a selection of events containing leptons and bottom-quark jets. No evidence for a significant excess of events over the standard model background prediction is observed. The results are interpreted in the context of simplified supersymmetric models with pair production of a heavier top-squark mass eigenstate tilde(t)_{2} decaying to a lighter top-squark mass eigenstate tilde(t)_{1} via either tilde(t)_{2} -> H tilde(t)_{1} or tilde(t)_{2} -> Z tilde(t)_{1}, followed in both cases by tilde(t)_{1} -> t tilde(chi)^{0}_{1}, where tilde(chi)^{0}_{1} is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between the tilde(t)_{1} and tilde(chi)^{0}_{1} states is approximately equal to the top-quark mass ( m(tilde(t)_{1}) - m(tilde(chi)^{0}_{1}) =~ m(t) ), which is not probed by searches for direct tilde(t)_{1} squark pair production. The analysis excludes top squarks with masses m(tilde(t)_{2}) < 575 GeV and m(tilde(t)_{1}) < 400 GeV at a 95% confidence level.

Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at sqrt(s) = 8 TeV / V. Khachatryan, A.M. Sirunyan, A. Tumasyan, W. Adam, T. Bergauer, M. Dragicevic, J. Ero, C. Fabjan, M. Friedl, R. Fruhwirth, V.M. Ghete, C. Hartl, N. Hormann, J. Hrubec, M. Jeitler, W. Kiesenhofer, V. Knunz, M. Krammer, I. Kratschmer, D. Liko, et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 736:(2014), pp. 371-397. [10.1016/j.physletb.2014.07.053]

Search for top-squark pairs decaying into Higgs or Z bosons in pp collisions at sqrt(s) = 8 TeV

CIULLI, VITALIANO;D'ALESSANDRO, RAFFAELLO;FOCARDI, ETTORE;GONZI, SANDRO;GORI, VALENTINA;LENZI, PIERGIULIO;TROPIANO, ANTONIO;
2014

Abstract

A search for supersymmetry through the direct pair production of top squarks, with Higgs (H) or Z bosons in the decay chain, is performed using a data sample of proton–proton collisions at sqrt(s) = 8 TeV collected in 2012 with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 19.5 fb^{-1}. The search is performed using a selection of events containing leptons and bottom-quark jets. No evidence for a significant excess of events over the standard model background prediction is observed. The results are interpreted in the context of simplified supersymmetric models with pair production of a heavier top-squark mass eigenstate tilde(t)_{2} decaying to a lighter top-squark mass eigenstate tilde(t)_{1} via either tilde(t)_{2} -> H tilde(t)_{1} or tilde(t)_{2} -> Z tilde(t)_{1}, followed in both cases by tilde(t)_{1} -> t tilde(chi)^{0}_{1}, where tilde(chi)^{0}_{1} is an undetected, stable, lightest supersymmetric particle. The interpretation is performed in the region where the mass difference between the tilde(t)_{1} and tilde(chi)^{0}_{1} states is approximately equal to the top-quark mass ( m(tilde(t)_{1}) - m(tilde(chi)^{0}_{1}) =~ m(t) ), which is not probed by searches for direct tilde(t)_{1} squark pair production. The analysis excludes top squarks with masses m(tilde(t)_{2}) < 575 GeV and m(tilde(t)_{1}) < 400 GeV at a 95% confidence level.
2014
736
371
397
V. Khachatryan; A.M. Sirunyan; A. Tumasyan; W. Adam; T. Bergauer; M. Dragicevic; J. Ero; C. Fabjan; M. Friedl; R. Fruhwirth; V.M. Ghete; C. Hartl; N. ...espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/891150
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