@misc{10481/85928,
year = {2023},
month = {9},
url = {https://hdl.handle.net/10481/85928},
abstract = {A search is presented for a heavy resonance Y decaying into a Standard Model Higgs boson H and a new particle X in a fully hadronic final state. The full Large Hadron Collider run 2 dataset of proton-proton collisions at √s=13  TeV collected by the ATLAS detector from 2015 to 2018 is used and corresponds to an integrated luminosity of 139  fb−1. The search targets the high Y-mass region, where the H and X have a significant Lorentz boost in the laboratory frame. A novel application of anomaly detection is used to define a general signal region, where events are selected solely because of their incompatibility with a learned background-only model. It is constructed using a jet-level tagger for signal-model-independent selection of the boosted X particle, representing the first application of fully unsupervised machine learning to an ATLAS analysis. Two additional signal regions are implemented to target a benchmark X decay into two quarks, covering topologies where the X is reconstructed as either a single large-radius jet or two small-radius jets. The analysis selects Higgs boson decays into b¯b, and a dedicated neural-network-based tagger provides sensitivity to the boosted heavy-flavor topology. No significant excess of data over the expected background is observed, and the results are presented as upper limits on the production cross section σ(pp→Y→XH→q¯qb¯b) for signals with mY between 1.5 and 6 TeV and mX between 65 and 3000 GeV.},
organization = {CERN},
organization = {MICINN, Spain},
organization = {European Cooperation in Science and Technology (COST)},
organization = {ERC},
organization = {ERDF},
organization = {Horizon 2020},
organization = {Marie Skłodowska-Curie Actions},
organization = {European Union},
organization = {La Caixa Banking Foundation},
organization = {CERCA Programme Generalitat de Catalunya},
organization = {PROMETEO},
organization = {GenT Programmes Generalitat Valenciana, Spain},
organization = {PIC (Spain)},
publisher = {American Physical Society},
title = {Anomaly detection search for new resonances decaying into a Higgs boson and a generic new particle X in hadronic final states using √s=13  TeV pp collisions with the ATLAS detector},
doi = {10.1103/PhysRevD.108.052009},
author = {Aad, G. and Aguilar Saavedra, Juan Antonio and Rodríguez Chala, Mikael and Atlas Collaboration},
}