Abstract
This paper presents a search for new heavy particles decaying into a pair of top quarks using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of sqrt{s} = 13 TeV with the ATLAS detector at the Large Hadron Collider. The search is performed using events consistent with pair production of high-transverse-momentum top quarks and their subsequent decays into the fully hadronic final states. The analysis is optimized for resonances decaying into a toverline{t} pair with mass above 1.4 TeV, exploiting a dedicated multivariate technique with jet substructure to identify hadronically decaying top quarks using large-radius jets and evaluating the background expectation from data. No significant deviation from the background prediction is observed. Limits are set on the production cross-section times branching fraction for the new Z′ boson in a topcolor-assisted-technicolor model. The Z′ boson masses below 3.9 and 4.7 TeV are excluded at 95% confidence level for the decay widths of 1% and 3%, respectively.
Highlights
Background estimationThe main backgrounds after applying the selection criteria described in section 4 are expected to arise from SM production of ttpairs and multijet events
This paper presents a search for new heavy particles decaying into a pair of top quarks using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy
The in the transverse detector (ID) consists of a silicon pixel tracker, a silicon microstrip tracker (SCT) and a transition radiation tracker, all immersed in a 2 T axial magnetic field, and provides chargedparticle tracking in the range |η| < 2.5
Summary
The ATLAS experiment uses a multipurpose, forward-backward symmetric detector with nearly 4π solid angle coverage, as described in refs. [21,22,23]. Detector (ID) surrounded by a thin superconducting solenoid, electromagnetic (EM) and hadronic calorimeters, and a muon spectrometer. The ID consists of a silicon pixel tracker, a silicon microstrip tracker (SCT) and a transition radiation tracker, all immersed in a 2 T axial magnetic field, and provides chargedparticle tracking in the range |η| < 2.5. The hadronic calorimetry is provided by a steel/scintillator tile sampling calorimeter in the central region (|η| < 1.7) and by a copper/LAr calorimeter in the endcap regions (1.5 < |η| < 3.2). The forward region (3.1 < |η| < 4.9) is instrumented with copper/LAr and tungsten/LAr calorimeter modules optimized for electromagnetic and hadronic measurements, respectively. Surrounding the calorimeters is a muon spectrometer that consists of three air-core superconducting toroidal magnets and tracking chambers, providing precision tracking for muons with |η| < 2.7 and trigger capability for |η| < 2.4. This is followed by a software-based trigger that reduces the accepted event rate to an average of 1 kHz by refining the level-1 trigger selection
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
