Measurement of top quark polarization in top-antitop events from proton-proton collisions at √s = 7 TeV using the ATLAS detector

This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4:7 fb<SUP>-1</SUP> of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at √s = 7 TeV. Final states containing one or two isolated lept...

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Autores principales: Alconada Verzini, María Josefina, Alonso, Francisco, Anduaga, Xabier Sebastián, Dova, María Teresa, Monticelli, Fernando Gabriel, Tripiana, Martín Fernando, The ATLAS Collaboration
Formato: Articulo
Lenguaje:Inglés
Publicado: 2013
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/85423
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Sumario:This Letter presents measurements of the polarization of the top quark in top-antitop quark pair events, using 4:7 fb<SUP>-1</SUP> of proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at √s = 7 TeV. Final states containing one or two isolated leptons (electrons or muons) and jets are considered. Two measurements of α<SUB>ℓ</SUB>P, the product of the leptonic spin-analyzing power and the top quark polarization, are performed assuming that the polarization is introduced by either a CP conserving or a maximally CP violating production process. The measurements obtained, α<SUB>ℓ</SUB>P<SUB>CPC</SUB>=–0.035 ± 0.014(stat) ± 0.037(syst) and α<SUB>ℓ</SUB>P<SUB>CPV</SUB>= 0.020 ± 0.016(stat)<SUP>+0.013</SUP> <SUB>-0.017</SUB>(syst), are in good agreement with the standard model prediction of negligible top quark polarization.