6533b871fe1ef96bd12d20d1

RESEARCH PRODUCT

Search for charginos nearly mass degenerate with the lightest neutralino based on a disappearing-track signature in pp collisions at root(s)=8 TeV with the ATLAS detector

Atlas CollaborationSusana Cabrera UrbánMaría Victoria Castillo GiménezMaría José Costa MezquitaFarida FassiAntonio Ferrer SoriaLuca FioriniJuan A. Fuster VerdúCarmen García GarcíaJosé Enrique García NavarroSantiago González De La HozYesenia Hernández JiménezEmilio Higón RodríguezAdrián Irles QuilesMohammed KaciCarlos Lacasta LlácerVicente Lacuesta MiquelLuis March RuizSalvador Martí GarcíaMercedes Miñano MoyaVasiliki MitsouRegina Moles VallsMaría Moreno LlácerElena Oliver GarcíaSebastián Pedraza LópezMaría Teresa Pérez García-estañE. Romero AdamEduardo Ros MartínezJosé Salt CairolsVictoria Sánchez MartínezU. SoldevilaJavier Sánchez MartínezEmma Torró PastorAlberto Valero BiotE. Valladolid GallegoJuan Antonio Valls FerrerMiguel Villaplana PérezMarcel Vos

subject

High Energy Physics::PhenomenologyFísicaHigh Energy Physics::Experiment

description

A search is presented for direct chargino production based on a disappearing-track signature using 20.3 fb(-1) of proton-proton collisions at root s = 8 TeV collected with the ATLAS experiment at the LHC. In anomaly-mediated supersymmetry breaking (AMSB) models, the lightest chargino is nearly mass degenerate with the lightest neutralino and its lifetime is long enough to be detected in the tracking detectors by identifying decays that result in tracks with no associated hits in the outer region of the tracking system. Some models with supersymmetry also predict charginos with a significant lifetime. This analysis attains sensitivity for charginos with a lifetime between 0.1 and 10 ns, and significantly surpasses the reach of the LEP experiments. No significant excess above the background expectation is observed for candidate tracks with large transverse momentum, and constraints on chargino properties are obtained. In the AMSB scenarios, a chargino mass below 270 GeV is excluded at 95% confidence level.

10.1103/physrevd.88.112006http://hdl.handle.net/10550/46727