Licentiate seminar by Alessandro Montella
Seminar
Date: Tuesday 16 December 2025
Time: 10.00 – 12.00
Location: Room C5:1007, Albanova universitetscentrum, Roslagstullsbacken 21, Stockholm
Licenciate thesis: Calibration of Hadronic Calorimeter Cells and New Physics Searches at the ATLAS experiment
Arrangör: Fysikum, Stockholm University
Zoom: Shall not be streamed online
Kontakt: Alessandro Montella
No registration required
Abstract:
This thesis presents two studies performed with the ATLAS detector at the Large Hadron Collider: a detector performance study of the ATLAS Tile Calorimeter E-cells and a search for new phenomena in tt? + Eᴛᵐ ˢˢⁱ final states. The detector performance study characterizes the energy response of the E-cells of the ATLAS Tile Calorimeter using isolated muons from W→μν events collected in proton-proton collisions at a √s = 13.6 TeV during LHC Run 3. The E-cells rely on a different energy calibration method from that of standard calorimeter cells. The study employs a novel noise-subtraction method to extract the muon signal in challenging high pile-up conditions. Data-to-simulation ratios are used to validate the energy scale calibration and assess response uniformity across the detector modules, while dedicated studies evaluate systematic effects of the noise-subtraction procedure. Year-to-year stability measurements demonstrate that the calibration remains consistent throughout Run 3 in the data-taking period 2022-2023. The search for new phenomena targets supersymmetric models with direct production of stop-quark pairs decaying to top quarks and the lightest neutralino, as well as dark matter models where a scalar or pseudoscalar mediator is produced in association with a tt? pair. The analysis uses final states with exactly one lepton, jets, and large missing transverse momentum in events from of proton-proton collisions at √s = 13 TeV collected during LHC Run 2. Event classification is performed using neural network-based discriminants trained separately for each signal model and kinematic category. No significant excess above the Standard Model prediction is observed and exclusion limits are set on the masses of the supersymmetric particles and dark matter mediators.
Last updated: November 26, 2025
Source: Fysikum