Documents in process

he top-quark Yukawa coupling is extracted from the distribution of the top-quark pair (t¯t) invariant mass in proton-proton collisions using 140fb−1 of data at √s=13 TeV collected in 2015-2018 by the ATLAS experiment at the Large Hadron Collider. In the region near the production threshold, the t¯t invariant mass spectrum is sensitive to electroweak virtual corrections, including contributions from Higgs boson exchange, thereby providing sensitivity to the top-quark Yukawa coupling. [...]

The exceptionally large dataset collected by the ATLAS detector at the highest proton-proton collision energies provided by the LHC enables precision testing of theoretical predictions using an extensive sample of top quark events. This wealth of data has also opened the door to new measurements including those particularly sensitive to the ttbar threshold region, such as measurement of enhancement of ttbar production due to non-relaticistic QCD effects in the threshold, and measurement of top-quark Yukawa coupling in the ttbar production. [...]

This talk highlights the challenges faced when attempting to measure quantum properties. In particular, difficulties in the identification of jet flavours and the reconstruction of ttbar systems will be considered, especially in the boosted topology where the decay products become highly collimated..

Electron CT (eCT) is a new imaging method, which uses multiple scattering of electrons to determine the material budget of objects. This method could be used as the imaging method for flash radiotherapy with Very High Energy Electrons (VHEE, 50-250 MeV). [...]

Following the discovery of the Higgs boson in 2012 by the ATLAS and CMS Collaborations, studies are required to investigate its Charge-Parity (CP) properties in the Yukawa interaction with tau leptons. This talk presents an ongoing master’s thesis in the µ a1 decay channel [...]

Highly energetic top quarks produced in proton-proton collisions at the LHC can result in decay products that are highly collimated, appearing as a single large-radius jet in the CMS detector. These jets exhibit a distinctive internal substructure, enabling discrimination between top quark jets and those arising from other QCD processes. [...]

There is current interest in searching for beyond the standard model particles produced in association with a top quark pair, tt + X(X→ t t). This project focuses on a top-philic Z* resonance model that may significantly enhance the tttt cross section [...]

We study the sensitivity to long-lived particles (LLPs) of a proposed circular electron-positron collider, the FCC-ee. The very low background environments in electron-positron collisions provide exciting opportunities to search for several types of LLPs. [...]