Ph.D. Theses

In this thesis, measurements performed using proton-proton collision data at $\sqrt{s} = 13$TeV collected by the CMS experiment at the CERN LHC, in the years 2016, 2017, and 2018, are presented. The data correspond to an integrated luminosity of 138$~\mathrm{fb}^{-1}$.New results on top quark pair production in association with a photon ($\mathrm{t\bar{t}\gamma}$) are presented. [...]

The dissociation dynamics of diiodomethane molecules (CH2I2) have been investigated in a 97.6 eV XUV-pump XUV-probe measurement at the reaction microscope endstation at the free-electron laser FLASH2. Ionic fragments created by 4d inner-valence ionisation followed by Auger decay have been detected in coincidence, enabling a kinematically complete reconstruction of the dissociation pathways [...]

This thesis presents the study of three quantum materials conducted by means of a novel photon source for Time- and Angle-Resolved Photoelectron Spectroscopy (TR-ARPES) developed at the T-ReX laboratory at FERMI (Elettra, Trieste). This source provides pulses at a photon energy of 10.8 eV up to the MHz repetition rate, while offering picosecond time resolution and few tens of meV energy resolution. [...]

This thesis is aimed at establishing modalities of time-resolved photoelectron spectroscopy (tr-PES) conducted at a free-electron laser (FEL) source and at a high harmonic generation (HHG) source for imaging the motion of atoms, charge and energy at photoexcited hybrid organic/inorganic interfaces. Transfer of charge and energy across interfaces lies at the heart of surface science and device physics and involves a complex interplay between the motion of electrons and atoms [...]

In this thesis the development of a time projection chamber (TPC) for the International Large Detector (ILD) concept at the International Linear Collider (ILC) is discussed and an analysis is carried out to evaluate the performance of the detector concept. The ILC is a planned linear electron-positron collider. [...]

With the advent of ultrafast optics and controllable waveforms consisting of only a few oscillations of the electric field, the idea of controlling electrons at the frequency of light was born. This established the potential of using a controlled optical waveform to switch electronic circuit elements at the frequency of an optical wave, typically on the order of 0.1 to 1 petahertz(1015 Hz). [...]

Novel all-optical terahertz (THz)-based accelerators promise to enable new science by providing ultrafast and bright electron bunches at a small footprint. While practical prototypes of THz-based devices have been demonstrated and have shown exceptional capabilities to accelerate and manipulate electron beams on sub-ps timescales, the development of practical THz-driven photoguns has lagged behind due to challenges associated with physical miniaturization and the high THz pulse energy required. [...]

Double parton scattering (DPS) describes a process in hadron-hadron scattering in which two partons are extracted from each initial hadron and then initiate hard scattering processes separated by a finite distance. After factorising the hadronic process, one obtains parton distributions functions that characterise the behaviour of partons inside the hadron at non-perturbative scales. [...]

Laser-wakefield acceleration (LWFA) is a promising, emerging technology for future accelerator-based X-ray light sources, which are essential tools in various fields of science, industry and medicine. In laser-wakefield acceleration, an intense laser pulse drives a plasma wave that supports high accelerating field gradients. [...]

The Large Hadron Collider (LHC) will undergo a major “High Luminosity” upgrade with the goal of delivering a peak instantaneous luminosity of 5 − 7.5 × 10^34 cm−2s−1 by 2029. In order for the CMS experiment to cope with the higher radiation levels and data rates, the current CMS Silicon Tracker will be replaced. [...]