Phenomenology of Vector-Like Quarks decaying into Beyond-the-Standard-Model particles at the LHC and tests of Inner Tracker modules for the ATLAS detector upgrade

  • Date: –11:30
  • Lecturer: Thomas Mathisen (Uppsala University)
  • Contact person: Rebeca Gonzalez Suarez
  • Seminarium

Half-time PhD seminar

This will be a virtual seminar, and will be hosted in Zoom


Meeting ID: 667 8666 4010

Half-time PhD seminar

If we assume the Standard Model of particle physics (SM) as an effective field theory, valid to a certain energy scale, it will lead to a hierarchy between two scales in the Higgs mass term. This leads to the fine-tuning in the theoretical calculation of the mass of the Higgs boson. Here we look into this problem and one possible solution, the Composite Higgs Model (CHM) where the Higgs boson will emerge as a bound state from a new strongly coupled sector. One of the predictions of CHMs at the TeV scale is the presence of Vector-Like Quarks (VLQ).

High-energy collider experiments, such as the ATLAS experiment at the LHC, have primarily focused on minimal CHM where the VLQ will only couple to SM particles. However, there is nothing to suggest that this is the entire picture. Depending on the symmetry groups and the breaking pattern additional pNGBs beyond the SM (BSM) can emerge which will couple to the VLQ and predict yet another decay channel to study. Here we look more into this particular scenario and focus on the top partner VLQ (t') and an additional exotic pNGB (S).

A phenomenological study will be presented were we illustrate a method to asses how the LHC would handle t' decays into new spin-0 states which can be either fundamental or composite. We develop a toy model, allowing for in principle any type of spin-0 state, for the purpose of this study and show that more specific and realistic models including a top partner t' and a new spin-0 state can be parameterized to such a toy model. In addition to this, an ATLAS analysis is ongoing continuing the work of the phenomenological study.

Furthermore, we will look into the issues of the major increase in data-rate at the LHC in a high luminosity (HL) scenario. Specifically we focus on the Inner Tracker (ITk) of the ATLAS detector and its readout architecture. The current design of the ATLAS detector is not suitable for the HL-LHC scenario. Thus, upgrades will have to be done to the detector, among these new trigger capabilities. As the trigger capabilities get updated it is crucial that the read-out architecture keeps up. Here, the development of a method to test the read-out hardware set of the ITk strip detector in the ATLAS detector to assess its performance under a HL-LHC scenario is presented.