Searching for new physics with MicroBooNE and development of a next generation neutrino detector

Abstract

The Standard Model (SM) theory of particle physics effectively explains the composition of the subatomic world. However, there are still some anomalous particle phenomena that are at odds with the theoretical predictions within the SM, leading to what is known as the new physics problem. Areas such as dark matter exploration and the study of CP violation have garnered significant research interest, consequently driving advancements in next-generation particle detectors. These detectors offer improved resolution and enhanced particle identification capabilities, facilitating more precise detection at low energies. The next generation neutrino experiment, DUNE, will use a technology called a liquid-argon time projection chamber (LArTPC). Within the DUNE LArTPC, multiple anode plane assemblies (APAs) will be implemented to accurately measure neutrino interactions. The extensive Copper-Beryllium wires within APAs can effectively capture the ionisation generated by charged particles resulting from interactions in liquid argon. An essential consideration for these APAs is ensuring the wires maintain the correct tension to ensure the wires deliver clear signal and maintain structural integrity. Given the extensive use of these APAs in DUNE's far detector, there arises a challenge in testing all the 150 APAs with about 2500 wires each. This thesis presents an innovative method for assessing wire tension. This new approach is not only faster than the current laser method but also yields precise results. It can simultaneously test multiple wires without requiring physical contact. The accuracy of this novel method is demonstrated through a comparison with results obtained using the laser method, utilizing data from a Far Detector-APA currently operational in the ProtoDUNE-2 TPC. Another neutrino experiment working on Fermilab’s Booster Neutrino Beamline (BNB) is MicroBooNE, which has an 85-tonne active mass LArTPC. In this thesis, we contribute to a search for new physics by assessing the sources of systematic uncertainty that will impact a search for sub-GeV dark-matter candidates in MicroBooNE. In the dark matter search, we will concentrate on the uncertainties of the neutrino interaction background. There are four main channels of uncertainty: detector-related variables, neutrino flux, neutrino cross-section, and hadron-argon re-interactions. We used re-simulation and re-weighting of the Monte Carlo samples to calculate the uncertainty from each source and apply these to update the sensitivity of the dark matter search.

Date of Award	9 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Stefan Söldner-Rembold (Co Supervisor) & Justin Evans (Main Supervisor)