A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3fb-1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in the azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38$\pm$0.04, in agreement with the standard model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95\% confidence level. \copyright 2015 CERN, for the ATLAS Collaboration.

Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at s =8TeV using the ATLAS detector / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; Chiefari, Giovanni; DELLA PIETRA, Massimo; DELLA VOLPE, Domenico; Merola, Leonardo; Patricelli, Sergio; Conventi, Francesco; Rossi, Elvira; Perrella, Sabrina; SANCHEZ PINEDA, ARTURO RODOLFO; Carlino, Gianpaolo; DE ASMUNDIS, Riccardo; DI DONATO, Camilla; Doria, Alessandra; Iengo, Paolo; Izzo, Vincenzo; Sekhniaidze, Givi; Giordano, Raffaele; Et, A. l.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 114:14(2015). [10.1103/PhysRevLett.114.142001]

Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at s =8TeV using the ATLAS detector

ALOISIO, ALBERTO;ALVIGGI, MARIAGRAZIA;CANALE, VINCENZO;CHIEFARI, GIOVANNI;DELLA PIETRA, MASSIMO;DELLA VOLPE, DOMENICO;MEROLA, LEONARDO;PATRICELLI, SERGIO;CONVENTI, FRANCESCO;ROSSI, ELVIRA;PERRELLA, SABRINA;SANCHEZ PINEDA, ARTURO RODOLFO;CARLINO, GIANPAOLO;DE ASMUNDIS, Riccardo;DI DONATO, CAMILLA;IENGO, PAOLO;IZZO, VINCENZO;GIORDANO, RAFFAELE;
2015

Abstract

A measurement of spin correlation in tt¯ production is presented using data collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 20.3fb-1. The correlation between the top and antitop quark spins is extracted from dilepton tt¯ events by using the difference in the azimuthal angle between the two charged leptons in the laboratory frame. In the helicity basis the measured degree of correlation corresponds to Ahelicity=0.38$\pm$0.04, in agreement with the standard model prediction. A search is performed for pair production of top squarks with masses close to the top quark mass decaying to predominantly right-handed top quarks and a light neutralino, the lightest supersymmetric particle. Top squarks with masses between the top quark mass and 191 GeV are excluded at the 95\% confidence level. \copyright 2015 CERN, for the ATLAS Collaboration.
2015
Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at s =8TeV using the ATLAS detector / Aad, G; Aloisio, Alberto; Alviggi, Mariagrazia; Canale, Vincenzo; Chiefari, Giovanni; DELLA PIETRA, Massimo; DELLA VOLPE, Domenico; Merola, Leonardo; Patricelli, Sergio; Conventi, Francesco; Rossi, Elvira; Perrella, Sabrina; SANCHEZ PINEDA, ARTURO RODOLFO; Carlino, Gianpaolo; DE ASMUNDIS, Riccardo; DI DONATO, Camilla; Doria, Alessandra; Iengo, Paolo; Izzo, Vincenzo; Sekhniaidze, Givi; Giordano, Raffaele; Et, A. l.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 114:14(2015). [10.1103/PhysRevLett.114.142001]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/638005
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