Ph.d. degree
The University of Sheffield, United Kingdom

Praveen Kumar

Supervisor: Prof. Vitaly Kudryavtsev

Keywords:

• DUNE
• LArTPC
• Calibration
• Cosmic-ray muons, Neutrinos

Abstract:

The Deep Underground Neutrino Experiment (DUNE) aims to set new limits on parameters associated with neutrino oscillations, neutrino astrophysics, and beyond the Standard Model (SM) searches such as nucleon decay.

DUNE will quantify the magnitude of CP violation in the lepton sector, and determine the neutrino mass ordering. These benefit highly from the large target mass and excellent imaging, tracking, and particle identification capabilities of Liquid Argon Time Projection Chambers (LArTPCs). Detector calibration is essential to make precise physics measurements. For instance, accurate energy reconstruction is necessary for measuring many of the aforementioned quantities with the precision required for discovering new physics and fully exploiting the capabilities of the detector. Cosmic muons are a freely available natural source of calorimetric data and can be used for calibrating various detector parameters. This thesis provides an analysis of simulated cosmic-ray muon events generated with the Muon Simulation Underground (MUSUN) generator in the DUNE horizontal drift (HD) far detector (FD). The study focuses on analysing the energy and angular distribution of various classes of muon events, as well as characterising the different particles produced by cosmic muon interactions. The analysis of $\pi^{0} \rightarrow 2\gamma$ events within the cosmic-ray muon sample is presented in this thesis with a detailed study of reconstructing electromagnetic showers. %With certain assumptions, the mass of $\pi^{0}$ can be reconstructed within the DUNE FD. The $\pi^{0}$ mass is reconstructed within the DUNE FD, yielding a value of $(136 \pm 7)~\si{MeV/c^{2}}$. Additionally, the thesis introduces methods for $dE/dx$ calibration using simulated and reconstructed muon tracks. A calibration constant $C_{\si{cal}} = (5.469 \pm 0.003)\times 10^{-3} \si{ADC \times tick/e}$ is obtained through a model-dependent calibration process, where 1 tick corresponds to 500~ns of sampling time of an ADC. Furthermore, a calibration technique is presented, demonstrating precise translation from $dQ/dx$ to $dE/dx$. This calibration method is applied to stopping muons, charged pions, and protons in the DUNE FD, addressing the measurement of energy loss in the detector volume. These are important calibrations of the DUNE FD and will contribute to achieving the exciting physics goals of the experiment.