Artículos de revistas
A search for ttbar resonances in the lepton plus jets final state with ATLAS using 4.7 fb-1 of pp collisions at √s = 7 TeV
Fecha
2013-07Registro en:
Aad, G.; Abajyan, T.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; et al.; A search for ttbar resonances in the lepton plus jets final state with ATLAS using 4.7 fb-1 of pp collisions at √s = 7 TeV; American Physical Society; Physical Review D: Particles, Fields, Gravitation and Cosmology; 88; 1; 7-2013; 12004-12024
1550-7998
Autor
Aad, G.
Abajyan, T.
Abbott, B.
Abdallah, J.
Abdel Khalek, S.
Alonso, Francisco
Anduaga, Xabier Sebastian
Dova, Maria Teresa
González Silva, María Laura
Monticelli, Fernando Gabriel
Otero y Garzon, Gustavo Javier
Piegaia, Ricardo Nestor
Romeo, Gaston Leonardo
Tripiana, Martin Fernando
Zhuang, X.
Zhuravlov, V.
Zieminska, D.
Zimin, N. I.
Zimmermann, R.
Zimmermann, S.
Zimmermann, S.
Ziolkowski, M.
Zitoun, R.
Živković, L.
Zmouchko, V. V.
Zobernig, G.
Zoccoli, A.
zur Nedden, M.
Zutshi, V.
Zwalinski, L.
Resumen
A search for new particles that decay into top quark pairs (ttbar) is performed with the ATLAS experiment at the LHC using an integrated luminosity of 4.7 fb^-1 of proton-proton (pp) collision data collected at a center-of-mass energy sqrt(s)=7 TeV. In the ttbar --> WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The ttbar system is reconstructed using both small-radius and large-radius jets, the latter being supplemented by a jet substructure analysis. A search for local excesses in the number of data events compared to the Standard Model expectation in the ttbar invariant mass spectrum is performed. No evidence for a ttbar resonance is found and 95% credibility-level limits on the production rate are determined for massive states predicted in two benchmark models. The upper limits on the cross section times branching ratio of a narrow Z' resonance range from 5.1 pb for a boson mass of 0.5 TeV to 0.03 pb for a mass of 3 TeV. A narrow leptophobic topcolor Z' resonance with a mass below 1.74 TeV is excluded. Limits are also derived for a broad color-octet resonance with Gamma/m = 15.3%. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.07 TeV.