2026/07/30 by ATLAS Collaboration
Physics and Astronomy · #hep-ex
42 pages in total, author list starting page 25, 6 figures, 2 tables, submitted to JHEP. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2019-02
arxiv created 2026/07/30 · arxiv updated 2026/07/31
A search for pair-produced vector-like T quarks (VLQs) is presented. Each VLQ is assumed to decay into a top quark and an exotic (pseudo)scalar S. The search targets events with at least one resonant S → γγ decay and large summed transverse momentum and missing transverse momentum from other final-state particles. The analysis uses data from pp collisions at a centre-of-mass energy of √(s) = 13 TeV recorded by the ATLAS detector from 2015 to 2018 and corresponding to an integrated luminosity of 140 fb-1. This is the first VLQ search performed in this final state. No significant excess over the Standard Model background is observed. The analysis is model-independent to a large extent but targets cascade decays into final states with electroweak bosons or tt. Results are provided in the form of upper limits on the fiducial cross-section times branching ratio as a function of the masses of the VLQ and the spin-0 particle. The fiducial volume is defined by kinematic requirements on the photons from the spin-0 decay.