Search for resonant pair production of Higgs bosons in the bb¯bb¯ final state using pp collisions at s√ = 13 TeV with the ATLAS detector
Physical Review D: Particles, Fields, Gravitation and Cosmology American Physical Society 105 (2022) 092002
Abstract:A search for resonant Higgs boson pair production in the 𝑏 ¯𝑏𝑏 ¯𝑏 final state is presented. The analysis uses 126–139 fb−1 of 𝑝𝑝 collision data at √𝑠 = 13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis is divided into two channels, targeting Higgs boson decays which are reconstructed as pairs of small-radius jets or as individual large-radius jets. Spin-0 and spin-2 benchmark signal models are considered, both of which correspond to resonant 𝐻𝐻 production via gluon–gluon fusion. The data are consistent with Standard Model predictions. Upper limits are set on the production cross-section times branching ratio to Higgs boson pairs of a new resonance in the mass range from 251 GeV to 5 TeV.
Tagging $b$ quarks at extreme energies without tracks
Journal of Physics G: Nuclear and Particle Physics Institute of Physics 43:8 (2016) 085001
Abstract:We describe a new hit-based b-tagging technique for high energy jets and study its performance with a Geant4-based simulation. The technique uses the fact that at sufficiently high energy a B meson or baryon can live long enough to traverse the inner layers of pixel detectors such as those in the ATLAS, ALICE, or CMS experiments prior to decay. By first defining a "jet" via the calorimeter, and then counting hits within that jet between pixel layers at increasing radii, we show it is possible to identify jets that contain b-quarks by detecting a jump in the number of hits without tracking requirements. We show that the technique maintains fiducial efficiency at TeV scale B hadron energies, far beyond the range of existing algorithms, and improves upon conventional b-taggers.
ATLAS b-jet identification performance and efficiency measurement with tt¯ events in pp collisions at s√=13 TeV
European Physical Journal C: Particles and Fields Springer 79:11 (2019) 970
Abstract:The algorithms used by the ATLAS Collaboration during Run 2 of the Large Hadron Collider to identify jets containing b-hadrons are presented. The performance of the algorithms is evaluated in the simulation and the efficiency with which these algorithms identify jets containing b-hadrons is measured in collision data. The measurement uses a likelihood-based method in a sample highly enriched in tt¯ events. The topology of the t→Wb decays is exploited to simultaneously measure both the jet flavour composition of the sample and the efficiency in a transverse momentum range from 20 to 600 GeV. The efficiency measurement is subsequently compared with that predicted by the simulation. The data used in this measurement, corresponding to a total integrated luminosity of 80.5 fb−1, were collected in proton–proton collisions during the years 2015–2017 at a centre-of-mass energy s√= 13 TeV. By simultaneously extracting both the efficiency and jet flavour composition, this measurement significantly improves the precision compared to previous results, with uncertainties ranging from 1 to 8% depending on the jet transverse momentum.
Searches for Dijet Resonances Using √s=13 TeV Proton-Proton Collision Data Recorded by the ATLAS Detector at the Large Hadron Collider Foreword
Chapter in SEARCHES FOR DIJET RESONANCES: USING (ROOT)S = 13 TEV PROTON-PROTON COLLISION DATA RECORDED BY THE ATLAS DETECTOR AT THE LARGE HADRON COLLIDER, (2018) V-+
Search for nonresonant pair production of Higgs bosons in the b¯bb¯b final state in pp collisions at √s=13 TeV with the ATLAS detector
Physical Review D American Physical Society 108:5 (2023) 52003