A search for new particles that decay into top quark pairs (t (t) over bar) 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 root s = 7 TeV. In the t (t) over bar) -> WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The t (t) over bar) 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 t (t) over bar) invariant mass spectrum is performed. No evidence for a t (t) over bar) 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 m 15.3%. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.07 TeV.

Search for t(t)over-bar resonances in the lepton plus jets final state with ATLAS using 4.7 fb(-1) of pp collisions at root s=7 TeV / G., A., T., A., B., A., J., A., S. A., K., A. A., A., O., A., R., A., B., A., M., A., O. S., A., H., A., H., A., Y., A., B. S., A., L., A., D. L., A., T. N., A., J., A., S., A., et al.. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 88:(2013), p. 012004. [10.1103/physrevd.88.012004]

Search for t(t)over-bar resonances in the lepton plus jets final state with ATLAS using 4.7 fb(-1) of pp collisions at root s=7 TeV

BAGNAIA, Paolo;BINI, Cesare;DIONISI, Carlo;GAUZZI, Paolo;GENTILE, Simonetta;GIAGU, Stefano;LACAVA, Francesco;LUCI, Claudio;MESSINA, Andrea;MONZANI, SIMONE;SOLFAROLI CAMILLOCCI, ELENA;VERDUCCI, MONICA;
2013

Abstract

A search for new particles that decay into top quark pairs (t (t) over bar) 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 root s = 7 TeV. In the t (t) over bar) -> WbWb decay, the lepton plus jets final state is used, where one W boson decays leptonically and the other hadronically. The t (t) over bar) 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 t (t) over bar) invariant mass spectrum is performed. No evidence for a t (t) over bar) 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 m 15.3%. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.07 TeV.
2013
01 Pubblicazione su rivista::01a Articolo in rivista
Search for t(t)over-bar resonances in the lepton plus jets final state with ATLAS using 4.7 fb(-1) of pp collisions at root s=7 TeV / G., A., T., A., B., A., J., A., S. A., K., A. A., A., O., A., R., A., B., A., M., A., O. S., A., H., A., H., A., Y., A., B. S., A., L., A., D. L., A., T. N., A., J., A., S., A., et al.. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 88:(2013), p. 012004. [10.1103/physrevd.88.012004]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/555830
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