TY - JOUR
T1 - Search for pair production of heavy top-like quarks decaying to a high-p(T) W boson and a b quark in the lepton plus jets final state at root s=7 TeV with the ATLAS detector
AU - Aad, A.
AU - Abajyan, T.
AU - Abbott, B.
AU - Abdallah, J.
AU - Khalek, S.A.
AU - Dam, Mogens
AU - Hansen, Jørgen Beck
AU - Hansen, Peter Henrik
AU - Hansen, Jørn Dines
AU - Hansen, John Renner
AU - Klinkby, Esben Bryndt
AU - Jørgensen, Morten Dam
AU - Boelaert, Nele Maria Philomena
AU - Heisterkamp, Simon Johann Franz
AU - Løvschall-Jensen, Ask Emil
AU - Mehlhase, Sascha
AU - Nilsson, Björn Stefan
AU - Petersen, Troels Christian
AU - Xella, Stefania
PY - 2013/1/29
Y1 - 2013/1/29
N2 - A search is presented for production of a heavy up-type quark (t′) together with its antiparticle, assuming a significant branching ratio for subsequent decay into a W boson and a b quark. The search is based on 4.7 fb−1 of pp collisions at s=7 TeV recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. Data are analyzed in the lepton + jets final state, characterized by a high-transverse-momentum isolated electron or muon, large missing transverse momentum and at least three jets. The analysis strategy relies on the substantial boost of the W bosons in the t′t¯′ signal when mt′ ≳400 GeV. No significant excess of events above the Standard Model expectation is observed and the result of the search is interpreted in the context of fourth-generation and vector-like quark models. Under the assumption of a branching ratio BR(t′→Wb)=1, a fourth-generation t′ quark with mass lower than 656 GeV is excluded at 95% confidence level. In addition, in light of the recent discovery of a new boson of mass ∼126 GeV at the LHC, upper limits are derived in the two-dimensional plane of BR(t′→Wb) versus BR(t′→Ht), where H is the Standard Model Higgs boson, for vector-like quarks of various masses.
AB - A search is presented for production of a heavy up-type quark (t′) together with its antiparticle, assuming a significant branching ratio for subsequent decay into a W boson and a b quark. The search is based on 4.7 fb−1 of pp collisions at s=7 TeV recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. Data are analyzed in the lepton + jets final state, characterized by a high-transverse-momentum isolated electron or muon, large missing transverse momentum and at least three jets. The analysis strategy relies on the substantial boost of the W bosons in the t′t¯′ signal when mt′ ≳400 GeV. No significant excess of events above the Standard Model expectation is observed and the result of the search is interpreted in the context of fourth-generation and vector-like quark models. Under the assumption of a branching ratio BR(t′→Wb)=1, a fourth-generation t′ quark with mass lower than 656 GeV is excluded at 95% confidence level. In addition, in light of the recent discovery of a new boson of mass ∼126 GeV at the LHC, upper limits are derived in the two-dimensional plane of BR(t′→Wb) versus BR(t′→Ht), where H is the Standard Model Higgs boson, for vector-like quarks of various masses.
U2 - 10.1016/j.physletb.2012.11.071
DO - 10.1016/j.physletb.2012.11.071
M3 - Journal article
SN - 0370-2693
VL - 718
SP - 1284
EP - 1302
JO - Physics Letters B
JF - Physics Letters B
IS - 4-5
ER -