Books

This dissertation presents a study of the spin-dependent production of the $\Lambda$ hyperon and the mechanisms of quark fragmentation, with a particular focus on data obtained from the HERMES experiment at DESY. The research explores the role of longitudinal spin effects in semi-inclusive deep-inelastic scattering. [...]

The rare decays B → Kν ¯ν represent a class of flavor-changing neutral current processes that are highlysuppressed in the Standard Model and thus serve as sensitive probes for new physics. These decays aretheoretically clean, with uncertainties primarily stemming from hadronic form factors, and their branchingfractions are predicted with high precision. [...]

Laser-plasma accelerators (LPAs) are a promising technology to build compact andcost-efficient accelerators for a variety of applications. To realize this promise, thereliability and long-term stability of the accelerated electrons have to be improved.Much of this improvement relates to the stability of the drive laser. [...]

In September 2017, a high-energy neutrino event detected by the IceCube Neutrino Observatory (IceCube-170922A) was associated, at the $3σ$ level, with a gamma-ray flare from the blazar TXS 0506+056. Cosmic rays that are accelerated in astrophysical sources can escape from their jets and interact with background radiation fields. [...]

Modern particle physics is extremely reliant on advanced instrumentation, in particular, detectors. One of the key technologies for current and future experiments is semiconductor detectors. [...]

The steady-state gamma-ray emission from the Sun is thought to consist of two emission components due to interactions with Galactic cosmic rays: (1) a hadronic disk component, and (2) a leptonic extended component peaking at the solar edge and extending into the heliosphere. The flux of these components is expected to vary with the 11 yr solar cycle, being highest during solar minimum and lowest during solar maximum, as it varies with the cosmic-ray flux. [...]

This thesis presents a comprehensive study of the single top quark production in association with a WZ boson pair (tWZ), culminating in the first observation of this process. Measurements of rare processes are crucial to improve our understanding of the Standard Model (SM) and improve the sensitivity to loop-induced new physics. [...]