• Browse all
A search for $t\overline{t}$ resonances using lepton-plus-jets events in proton-proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

The collaboration
JHEP 1508 (2015) 148, 2015

Abstract (data abstract)
A search for new particles that decay into top quark pairs is reported. The search is performed with the ATLAS experiment at the LHC using an integrated luminosity of 20.3 fb-1 of proton-proton collision data collected at a centre-of-mass energy of $\sqrt{s}= 8$ TeV. The lepton-plus-jets final state is used, where the top pair decays to $W^+bW^-\bar{b}$, with one W boson decaying leptonically and the other hadronically. The invariant mass spectrum of top quark pairs is examined for local excesses or deficits that are inconsistent with the Standard Model predictions. No evidence for a top quark pair resonance is found, and 95% confidence-level limits on the production rate are determined for massive states in benchmark models. The upper limits on the cross-section times branching ratio of a narrow Z' boson decaying to top pairs range from 4.2 pb to 0.03 pb for resonance masses from 0.4 TeV to 3.0 TeV. A narrow leptophobic topcolour Z' boson with mass below 1.8 TeV is excluded. Upper limits are set on the cross-section times branching ratio for a broad colour-octet resonance with $\Gamma$/m= 15% decaying to $t\bar{t}$. These range from 2.5 pb to 0.03 pb for masses from 0.4 TeV to 3.0 TeV. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.2 TeV.

• #### Table 1

Data from Figure 1a

10.17182/hepdata.70548.v1/t1

Selection efficiency x Acceptance for a Z' resonance.

• #### Table 2

Data from Figure 1b

10.17182/hepdata.70548.v1/t2

Selection efficiency x Acceptance for a KK gluon resonance.

• #### Table 3

Data from Figure 1c

10.17182/hepdata.70548.v1/t3

Selection efficiency x Acceptance for a KK graviton resonance.

• #### Table 4

Data from Figure 1d

10.17182/hepdata.70548.v1/t4

Selection efficiency x Acceptance for a spin-0 resonance.

• #### Table 5

Data from Figure 10a

10.17182/hepdata.70548.v1/t5

Reconstructed m_tt spectrum for the boosted selections.

• #### Table 6

Data from Figure 10b

10.17182/hepdata.70548.v1/t6

Reconstructed m_tt spectrum for the resolved selections.

• #### Table 7

Data from Figure 10c

10.17182/hepdata.70548.v1/t7

Reconstructed m_tt spectrum for the all the selections.

• #### Table 8

Data from Figure 11a

10.17182/hepdata.70548.v1/t8

Limits on the production cross-section x branching ratio to tt final states as a function of the mass of Z'TC2.

• #### Table 9

Data from Figure 11c

10.17182/hepdata.70548.v1/t9

Limits on the production cross-section x branching ratio to tt final states as a function of the mass of bulk...

• #### Table 10

Data from Figure 11b

10.17182/hepdata.70548.v1/t10

Limits on the production cross-section x branching ratio to tt final states as a function of the mass of bulk...

• #### Table 11

Data from Figure 11d

10.17182/hepdata.70548.v1/t11

Limits on the production cross-section x branching ratio to tt final states as a function of the mass of a...

• #### Table 12

Data from Figure 12a

10.17182/hepdata.70548.v1/t12

Limits on the production cross-section x branching ratio to tt final states as a function of the width of a...

• #### Table 13

Data from Figure 13a

10.17182/hepdata.70548.v1/t13

Limits on the production cross-section x branching ratio to tt final states as a function of the width of a...

• #### Table 14

Data from Figure 14a

10.17182/hepdata.70548.v1/t14

Limits on the production cross-section x branching ratio to tt final states as a function of the width of a...

• #### Table 15

Data from Figure Aux. 3

10.17182/hepdata.70548.v1/t15

Migration from the true mtt values to the reconstructed mtt values for the resolved selection.

• #### Table 16

Data from Figure Aux. 4

10.17182/hepdata.70548.v1/t16

Migration from the true mtt values to the reconstructed mtt values for the boosted selection.

Loading Data...