MSc thesis defense by Kasper Pedersen

Title: Advancing New Reconstruction Techniques For Neutrino Detectors

Abstract:

The IceCube neutrino observatory is sensitive to measuring neutrinos in the O(1-100) GeV regime, allowing for world-leading measurements of neutrino oscillation parameters. An essential part of maximizing the sensitivity of the oscillation analyses is being able to precisely and accurately reconstruct the parameters of the detected neutrinos. In this work, a likelihood based reconstruction method utilizing direct simulation to generate hypotheses of neutrino events has been advanced. This is done by low level testing of the generation of MC data, as well as an exploration of the quality of the likelihood space.

The current method of generating MC data is shown to build on wrong assumptions of constituents cancelling out. This issue has been resolved to create the optimal conditions for reconstruction. Even when optimizing the conditions for the likelihood space, the reconstruction method underperforms expectations when considering energy reconstruction. With a precision of 10% on average and an accuracy comparable to the seeding the energy reconstruction still remains an issue in low energy reconstruction. These is- sues seem to stem from the minimizer’s ability to properly explore the likelihood space. The reconstruction method is shown to be a viable method of reconstructing particle parameters albeit work needs to be done before the method is competitive when compared to other current reconstruction methods. The reconstruction of the interaction vertex and azimuthal direction show very promising results, especially the reconstruction of the Z vertex is shown to perform extremely well. Here the direct simulation method reconstructs within 61 cm on average.

Please notice that the MSc thesis defense will take place virtually via Zoom. To receive a link to join the MSc thesis defense, please send an e-mail in advance to Jason Koskinen: koskinen@nbi.ku.dk