[Paper Review] High Energy Physics Opportunities Using Reactor Antineutrinos

Oluwatomi A. Akindele, J. M. Berryman+15 more|arXiv (Cornell University)|Mar 14, 2022

Neutrino Physics Research9 citations

TL;DR

This Snowmass 2021 white paper advocates for expanded use of reactor antineutrinos in high-energy physics, highlighting their role in probing three-neutrino oscillations, non-standard interactions, sterile neutrino searches, and coherent elastic neutrino-nucleus scattering (CEvNS). It emphasizes synergies between fundamental physics and applications in nuclear safeguards, advocating for coordinated technology development and workforce training to advance both research and societal impact.

ABSTRACT

Nuclear reactors are uniquely powerful, abundant, and flavor-pure sources of antineutrinos that continue to play a vital role in the US neutrino physics program. The US reactor antineutrino physics community is a diverse interest group encompassing many detection technologies and many particle physics topics, including Standard Model and short-baseline oscillations, BSM physics searches, and reactor flux and spectrum modeling. The community's aims offer strong complimentary with numerous aspects of the wider US neutrino program and have direct relevance to most of the topical sub-groups composing the Snowmass 2021 Neutrino Frontier. Reactor neutrino experiments also have a direct societal impact and have become a strong workforce and technology development pipeline for DOE National Laboratories and universities. This white paper, prepared as a submission to the Snowmass 2021 community organizing exercise, will survey the state of the reactor antineutrino physics field and summarize the ways in which current and future reactor antineutrino experiments can play a critical role in advancing the field of particle physics in the next decade.

Motivation & Objective

• To assess the current state and future potential of reactor antineutrino physics in advancing the US neutrino program.
• To identify synergies between fundamental neutrino physics and applied applications such as nuclear safeguards and reactor monitoring.
• To promote coordinated technology development for low-energy detection, IBD, and CEvNS to enhance sensitivity to new physics.
• To strengthen the workforce pipeline by integrating early-career physicists in both HEP and applied neutrino research.
• To advocate for coordinated investments and community engagement between fundamental physics and application-focused neutrino detection efforts.

Proposed method

• Systematic review of existing reactor antineutrino experiments (e.g., Daya Bay, RENO, KAML) and their contributions to oscillation and flux measurements.
• Analysis of reactor neutrino spectra and flux models, identifying discrepancies between data and predictions to guide improved theoretical frameworks.
• Evaluation of detection technologies, including inverse beta decay (IBD) and coherent elastic neutrino-nucleus scattering (CEvNS), with focus on low-threshold and high-resolution systems.
• Exploration of mobile and compact detector designs for long-baseline and near-field applications, including deployment at research and test reactors.
• Integration of reactor neutrino data with nuclear physics models to refine isotopic emission predictions and reduce systematic uncertainties.
• Identification of overlapping technological needs between high-energy physics and non-proliferation applications, such as low-background, high-efficiency, and directional detection.

Experimental results

Research questions

• RQ1 How can reactor antineutrino experiments improve constraints on three-neutrino oscillation parameters and resolve the reactor antineutrino anomaly?
• RQ2 What is the sensitivity of reactor-based experiments to non-standard neutrino interactions and sterile neutrino states?
• RQ3 Can coherent elastic neutrino-nucleus scattering (CEvNS) be detected at reactors with low-threshold detectors, and what physics would it unlock?
• RQ4 How can improved reactor neutrino flux and spectrum models reduce uncertainties in BSM searches and enhance detection sensitivity?
• RQ5 What synergies exist between fundamental neutrino physics and applied neutrino detection for nuclear safeguards and non-proliferation?

Key findings

• Reactor antineutrinos provide a flavor-pure, abundant source of MeV-scale antineutrinos, with ~2×10²⁰ antineutrinos produced per GWₜₕ of thermal power.
• The reactor antineutrino anomaly—discrepancy between predicted and measured spectra—remains unresolved and may signal new physics, including sterile neutrinos or flux model deficiencies.
• Medium- and long-baseline reactor experiments can probe short-baseline oscillations and reduce uncertainties in mixing parameters, especially when combined with near-field measurements.
• Detection of CEvNS at reactors is challenging but achievable with low-threshold, high-resolution detectors, offering access to physics below the IBD threshold and enabling new applications.
• Mobile and compact detectors developed for safeguards applications can directly support short-baseline sterile neutrino searches, demonstrating dual-use potential.
• Coordination between HEP and application communities can reduce redundant technology development and accelerate progress in both fundamental physics and non-proliferation monitoring.