One of the greatest remaining puzzles in physics is what particle dark matter consists of. For this project, the theory of dark pions is considered, a Hidden Valley model that extends the Standard...Show moreOne of the greatest remaining puzzles in physics is what particle dark matter consists of. For this project, the theory of dark pions is considered, a Hidden Valley model that extends the Standard Model with new, dark particles and a new force, dark QCD. A sensitivity study is performed to determine how many dark pions are expected to be in acceptance of the LHCb detector for Run 2 conditions; the LHCb is well-suited to search for particles in the considered O(1) GeV mass and O(1) - O(100) ps lifetime range. Additionally, a framework has been developed to study the dependence of the sensitivity on a number of theoretical parameters of the dark QCD model, namely the probability to form a dark vector meson instead of a dark pion, the number of colours in dark QCD, the dark QCD scale, and the Higgs mass. It is found that O(100) dark pions are in LHCb acceptance for different track categories, and that the considered the- oretical parameters do not drastically change the number of expected particles (with some small caveats), staying within a difference of about 20%. This is acceptable given the expected experimental uncertainty, showing theory inde- pendent searches for dark pions are possible.Show less
Acoustic neutrino detection is a promising method to observe ultra high energy neutrinos. These neutrino with energies larger than 10$^{18}$ eV have a relatively low expected flux, thus a large...Show moreAcoustic neutrino detection is a promising method to observe ultra high energy neutrinos. These neutrino with energies larger than 10$^{18}$ eV have a relatively low expected flux, thus a large instrumented volume is required. Current estimations give an instrumented volume of around O(100) km$^3$ using hydrophones as the detection modules. Measuring ultra high energy neutrino would provide us with crucial information on extragalactic sources, the GZK cut-off, and also the C$\nu$B. In this work, an event detection algorithm based on clique, a subspace clustering algorithm, was developed. Furthermore, a first look at event reconstruction was taken. Ultra high energy neutrino events with energies of roughly 5 $\cdot$ 10$^{19}$ eV were approximated by using their characteristic pancake shape. An instrumented volume of 4 km$^3$ was simulated. The study has shown that a hydrophone density of 400 per km$^3$ would provide the desired detection efficiency of near 100\%. At these values a noise rate of 5 Hz can be suppressed using an amplitude criterion besides a causality one. A causality criterion alone suppresses a noise rate of 0.5-0.6 Hz. Furthermore, it was found that a configuration utilizing multiple detector blocks would maximize the effective volume of the detector. Moreover, the hydrophones should be designed for a sensitivity in the range of 0-15 kHz. The reconstruction algorithm tested did not provide the desired results, it is recommended to develop an algorithm specifically for acoustic neutrino detection. We found that design of the detector is a balancing act between detection efficiency, detector size, and noise suppression. Finally, this study demonstrates the possibility of using a clique based approach for event detection in ultra high energy neutrino detection. However, we recommend the development of noise suppression algorithms at the single waveform level, as suppression of a noise rate of 0.5-0.6 Hz or 5 Hz, depending on match criteria, is not enough based on previous research, in which noise rates can be as high as 26 Hz in low noise environments. Machine learning approaches show the most promise here.Show less
Supernovae are powerful cosmic explosions that usually occur within their host galaxies. However, recent observations have discovered a small but growing number of supernovae located outside of...Show moreSupernovae are powerful cosmic explosions that usually occur within their host galaxies. However, recent observations have discovered a small but growing number of supernovae located outside of their host galaxies, known as orphan supernovae. This thesis project aims to investigate these peculiar events and their host environments to gain insights into the mechanisms that drive them. The objectives include analyzing a large sample of supernovae and determining if we actually observe a population of orphan supernovae. The methodology involves data analysis and theoretical modeling, utilizing public catalogs, archival data, and wide-field surveys.Show less
