Recent advancements in algorithm development have enabled researchers to tag new “flavours” of quarks, such as top and charm quarks.


Tops, charms and a dash of MET

Advancements in Particle Tagging for Discovering New Physics at CERN
Figure 1: Exclusion limits at the 95% confidence level on the supersymmetric-top quark mass. The BR scan interprets different levels of flavour mixing between the second and third quark generations in Supersymmetry models. (Image: ATLAS Collaboration/CERN)
Physics,ATLAS
Figure 2: Exclusion limits at the 95% confidence level on the supersymmetric-charm or -top quark mass. Improved charm-tagging algorithms and the Recursive Jigsaw Reconstruction technique allowed higher experimental reach by ~100 GeV for the compressed Supersymmetric mass spectra. (Image: ATLAS Collaboration/CERN)

These major searches highlight the power of advanced particle tagging techniques and machine-learning methods in the ongoing search for new-physics phenomena.


Setting new limits

Physics,ATLAS
Figure 3: Exclusion limits at 95% confidence level for up-type scalar leptoquarks coupled to first-generation leptons. This high BR and low mass (thus high production cross-section) region is excluded for the first time at the LHC. (Image: ATLAS Collaboration/CERN)

About the event display: A reconstruction of a proton-proton collision at 13 TeV from 2018, classified as very “signal-like” by neural networks. Orange lines trace particle trajectories while green and yellow blocks show calorimeter energy deposits. The blue line marks the muon’s path and yellow cones represent four reconstructed jets. The three closest jets form the hadronic top-quark candidate, identified by the neural-network classifier, while the remaining jet is a b-tagged jet which, together with the muon, form the leptonic top-quark candidate. The white dashed line indicates a missing momentum of 544 GeV. (Image: ATLAS Collaboration/CERN)

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