[Paper Review] Low-Energy Physics in Neutrino LArTPCs

D. Caratelli, W. Foreman+287 more|arXiv (Cornell University)|Mar 1, 2022

Neutrino Physics Research4 citations

TL;DR

This white paper outlines the scientific potential and technical challenges of detecting and reconstructing low-energy (sub-100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. It advocates for enhanced low-energy sensitivity through improved calibration, background control, novel detector technologies, and specialized data acquisition and reconstruction strategies to unlock new physics in neutrino oscillations and beyond-Standard Model (BSM) searches.

ABSTRACT

In this white paper, we outline some of the scientific opportunities and challenges related to detection and reconstruction of low-energy (less than 100 MeV) signatures in liquid argon time-projection chamber (LArTPC) detectors. Key takeaways are summarized as follows. 1) LArTPCs have unique sensitivity to a range of physics and astrophysics signatures via detection of event features at and below the few tens of MeV range. 2) Low-energy signatures are an integral part of GeV-scale accelerator neutrino interaction final states, and their reconstruction can enhance the oscillation physics sensitivities of LArTPC experiments. 3) BSM signals from accelerator and natural sources also generate diverse signatures in the low-energy range, and reconstruction of these signatures can increase the breadth of BSM scenarios accessible in LArTPC-based searches. 4) Neutrino interaction cross sections and other nuclear physics processes in argon relevant to sub-hundred-MeV LArTPC signatures are poorly understood. Improved theory and experimental measurements are needed. Pion decay-at-rest sources and charged particle and neutron test beams are ideal facilities for experimentally improving this understanding. 5) There are specific calibration needs in the low-energy range, as well as specific needs for control and understanding of radiological and cosmogenic backgrounds. 6) Novel ideas for future LArTPC technology that enhance low-energy capabilities should be explored. These include novel charge enhancement and readout systems, enhanced photon detection, low radioactivity argon, and xenon doping. 7) Low-energy signatures, whether steady-state or part of a supernova burst or larger GeV-scale event topology, have specific triggering, DAQ and reconstruction requirements that must be addressed outside the scope of conventional GeV-scale data collection and analysis pathways.

Motivation & Objective

• To identify and prioritize low-energy physics opportunities in LArTPC detectors below 100 MeV.
• To address the lack of understanding in sub-hundred-MeV neutrino interaction cross sections and nuclear physics in argon.
• To define calibration and background control requirements specific to low-energy signatures.
• To propose new detector technologies—such as charge enhancement, photon detection, low-radioactivity argon, and xenon doping—to improve low-energy sensitivity.
• To establish dedicated data acquisition, triggering, and reconstruction frameworks tailored for low-energy event topologies.

Proposed method

• Systematic review of low-energy signatures in GeV-scale neutrino interactions, emphasizing sub-100 MeV final-state particles.
• Identification of key experimental facilities—pion decay-at-rest sources, charged particle, and neutron beams—for measuring low-energy cross sections.
• Proposal of novel LArTPC technologies, including enhanced charge readout systems and photon detection, to improve low-energy signal detection.
• Development of dedicated calibration strategies for low-energy energy deposits and ionization signals.
• Design of specialized data acquisition and reconstruction pipelines to handle low-energy event topologies distinct from conventional GeV-scale analysis.
• Integration of radiological and cosmogenic background modeling to ensure low-energy signal purity.

Experimental results

Research questions

• RQ1 What low-energy signatures in LArTPCs are accessible to current and future neutrino experiments, and how do they enhance oscillation physics sensitivity?
• RQ2 How can low-energy neutrino interactions and nuclear processes in argon be better understood experimentally and theoretically at sub-100 MeV?
• RQ3 What calibration techniques and background controls are required to reliably detect and reconstruct low-energy events in LArTPCs?
• RQ4 Which novel detector technologies can significantly improve low-energy sensitivity in LArTPCs?
• RQ5 How can data acquisition and reconstruction systems be adapted to efficiently capture and analyze low-energy event topologies?

Key findings

• LArTPCs possess unique sensitivity to low-energy physics signatures, including sub-100 MeV final states in neutrino interactions, enabling enhanced oscillation physics sensitivity.
• Low-energy signatures are critical components of GeV-scale neutrino interactions and are essential for full event reconstruction and physics reach.
• Current theoretical and experimental understanding of sub-hundred-MeV neutrino cross sections and nuclear processes in argon remains inadequate, necessitating new measurements.
• Pion decay-at-rest sources and charged particle and neutron test beams are identified as ideal facilities for improving low-energy cross section measurements.
• Novel technologies such as charge enhancement, photon detection, low-radioactivity argon, and xenon doping are proposed to significantly enhance low-energy detection capabilities.
• Dedicated triggering, DAQ, and reconstruction systems are required for low-energy events, as conventional GeV-scale pipelines are insufficient for sub-100 MeV physics.