Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume II: DUNE Physics (2002.03005v2)

Abstract: The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume II of this TDR, DUNE Physics, describes the array of identified scientific opportunities and key goals. Crucially, we also report our best current understanding of the capability of DUNE to realize these goals, along with the detailed arguments and investigations on which this understanding is based. This TDR volume documents the scientific basis underlying the conception and design of the LBNF/DUNE experimental configurations. As a result, the description of DUNE's experimental capabilities constitutes the bulk of the document. Key linkages between requirements for successful execution of the physics program and primary specifications of the experimental configurations are drawn and summarized. This document also serves a wider purpose as a statement on the scientific potential of DUNE as a central component within a global program of frontier theoretical and experimental particle physics research. Thus, the presentation also aims to serve as a resource for the particle physics community at large.

• The paper advances neutrino physics by detailing DUNE’s approach to measuring CP violation and determining the neutrino mass hierarchy.
• It leverages a long-baseline beam and LArTPC detectors to capture precise oscillation data over a 1300 km distance.
• Advanced simulations and calibration techniques underpin the experiment’s goal of achieving sub-percent precision in key parameters.

Review of the DUNE Technical Design Report: Physics Volume

The Deep Underground Neutrino Experiment (DUNE) represents a significant advance in neutrino observatories, aiming to unravel fundamental particles' mysteries and interactions. Hosted by Fermilab, DUNE plans to deploy cutting-edge liquid argon time-projection chambers (LArTPCs) at the Sanford Underground Research Facility. This review focuses on the Physics volume of the DUNE Technical Design Report, summarizing its scientific objectives and the theoretical framework underpinning the experiment.

Scientific Objectives and Theoretical Context

DUNE's primary goal is to elucidate the phenomena of neutrino oscillations, which manifest due to neutrino mixing—the transformation between neutrino flavor and mass eigenstates, parameterized by the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) matrix. The experiment's main objectives include:

1. CP Violation in the Lepton Sector: By comparing neutrino and antineutrino oscillations, DUNE aims to determine the CP-violating phase in the PMNS matrix, which could provide insight into the matter-antimatter asymmetry in the Universe.
2. Neutrino Mass Hierarchy: The experiment seeks to resolve whether the neutrino mass ordering is normal ($m_1 < m_2 < m_3$) or inverted ($m_3 < m_1 < m_2$), providing crucial information about neutrino mass generation mechanisms.
3. Precision Measurement of Oscillation Parameters: DUNE will conduct precise measurements of known parameters, such as $\theta_{23}$, aiming to determine its octant and refine the measurements of $\theta_{12}$ and $\theta_{13}$.

These goals relate to broad questions in particle physics, such as the nature of the neutrino masses, potential new symmetries, and differences between quark and lepton mixing.

Experimental Setup and Methodology

DUNE's design leverages a powerful neutrino beam from Fermilab to the LArTPC detectors located 1300 km away. This long baseline enhances the experiment's sensitivity to the oscillation patterns affected by matter effects, crucial for resolving the mass hierarchy. The wide-band beam spans energies from less than 1 GeV to several GeVs, allowing paper across multiple oscillation maxima—a key advantage for investigating both CP violation and resolving degeneracies in oscillation parameters.

Simulations, Reconstruction, and Calibration

State-of-the-art computational models and simulation tools underpin DUNE's readiness to achieve its ambitious goals. The GEANT4-based G4LBNF simulates the beamline, while GENIE handles neutrino interactions within the detector. Reconstruction algorithms, such as the charge clustering and hit-finding modules, enable 3D tracking and calorimetric energy estimations to precisely determine neutrino interaction properties.

Calibration systems, including laser-induced ionization techniques and monitoring via cosmic rays, will ensure robust measurement accuracy, vital for reducing systematic uncertainties. These endeavors highlight the depth of preparation toward achieving sub-percent precision in essential parameters.

Implications and Future Directions

DUNE's results promise significant breakthroughs. A definitive measurement or limit on lepontic CP violation would impact theories of baryogenesis and neutrino mass generation. Additionally, unambiguously resolving the mass hierarchy will strongly constrain models beyond the Standard Model, while precise parameter measurements could reveal new physics.

Concurrently, DUNE will serve a broader scientific community by providing complementary data sets for neutrinoless double-beta decay experiments and cosmological studies on neutrino masses. This collaboration will advance experimental methodologies and theoretical models across multiple physics domains.

In conclusion, DUNE represents a monumental step forward in neutrino physics, promising to address vital unresolved questions about the universe's fundamental forces and constituents. The comprehensive technical and strategic planning outlined in its Physics volume indicates a rigorous path towards achieving these scientific milestones.