10.1007-JHEP08(2015)148.pdf (1.64 MB)
A search for tt¯ resonances using lepton-plus-jets events in proton-proton collisions at vs = 8 TeV with the ATLAS detector
journal contribution
posted on 2023-06-09, 05:46 authored by Benedict AllbrookeBenedict Allbrooke, Lily AsquithLily Asquith, Alessandro CerriAlessandro Cerri, C A Chavez Barajas, Antonella De SantoAntonella De Santo, Fabrizio SalvatoreFabrizio Salvatore, I Santoyo Castillo, K Suruliz, Mark SuttonMark Sutton, Iacopo Vivarelli, The ATLAS CollaborationA 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 vs=8 TeV. The lepton-plus-jets final state is used, where the top pair decays to W+bW-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 G/m = 15% decaying to tt¯. These range from 4.8 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.
Funding
ATLAS; G0275; STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCIL; ST/I006048/1
History
Publication status
- Published
File Version
- Published version
Journal
Journal of High Energy PhysicsISSN
1029-8479Publisher
Springer VerlagExternal DOI
Issue
8Volume
2015Article number
a148Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Experimental Particle Physics Research Group Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2017-04-11First Open Access (FOA) Date
2017-04-11First Compliant Deposit (FCD) Date
2017-04-11Usage metrics
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