Powered by Indico
v3.2.9
Abstract:
The naturalness problem of the Standard Model (SM) challenges our understanding of the origin of mass due to to the fine-tuning problem of the Higgs mass. Several theories have been proposed to tackle the problem out of which one is the Composite Higgs Model (CHM). The theory considers a symmetry group of a new strong sector which is broken spontaneously as the energy is lowered. The Higgs boson emerges out of the spontaneously broken symmetry as a pseudo Nambu-Goldstone Boson (pNGB). In such a scenario the Higgs boson of the SM is not an elementary scalar but instead a composite object and the fine-tuning of the Higgs mass is reduced. Consequences of the CHM are new states, both scalars, and fermions so called Vector-Like Quarks (VLQ), with masses low enough to be produced at the LHC.
In this presentation a phenomenological study of a VLQ with an additional scalar or pseduoscalar is shown. The VLQ will couple to the SM top quark and the scalar S. Here such a decay will be looked at in more detail, quantifying the sensitivity of such a search to the current experiments at the LHC with the case of the scalar S decaying to either a diphoton or a Z+photon final state. The analysis is model independent using a simplified model capturing all the relevant features from other more realistic models. The sensitivity results can thus be interpreted in other models, something that is demonstrated using the CHM and the 2HDM+VLQ model.
In ATLAS there are current searches for the VLQs. However, all such searches focus on a minimal case where the VLQ decays into known SM particles. We continue the phenomenological study into the ATLAS experiment focusing on an exotic decay of the VLQ decaying into a SM top and a new Beyond the SM scalar S with a diphoton final state. The background modeling will be covered and expected limits will be presented.
The ATLAS experiment at the LHC is reaching its limit in energy and luminosity. The next step is an upgrade to the High-Luminosity LHC (HL-LHC) significantly raising the data rates. For the ATLAS experiment to cope with the data rates delivered by the HL-LHC, the detector needs to the upgraded. Among the many upgrades planned is a new Inner Tracker (ITk) with new trigger capabilities. Initially a two-level trigger was planned. In this presentation a development of test procedure for the two-level trigger and readout scheme for the ITk Strip module is shown. It will cover in detail the current bunch filling of the LHC which will be accurately simulated such that a realistic trigger pattern can be used for the test program. Additionally, a first run of the test procedure with a single-level trigger is shown.