arxiv: 2604.20957 · v1 · submitted 2026-04-22 · ✦ hep-ex

Recognition: unknown

Enhanced Reconstruction of Sub-GeV Neutrinos Charged Current Interactions in LArTPC

Stone Chou , Sanskar Jain , Wei Shi , Ciro Riccio

Authors on Pith no claims yet

Pith reviewed 2026-05-09 22:24 UTC · model grok-4.3

classification ✦ hep-ex

keywords LArTPCneutrino reconstructionscintillation lightcharge calorimetryneutrino antineutrino separationdirection reconstructionsub-GeV neutrinosatmospheric neutrinos

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The pith

Combining charge and light signals in LArTPCs separates electron neutrinos from antineutrinos with 70% efficiency and improves direction reconstruction.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes that charge-based calorimetry alone is insufficient for accurate energy reconstruction of sub-GeV neutrinos in LArTPCs due to recombination fluctuations and missing hadronic energy. It shows that incorporating scintillation light, which exhibits a self-compensating effect, improves performance especially above 400 MeV, with comparable results below 300 MeV. Combining both types of signals enables 70% efficient separation of electron neutrinos and antineutrinos. A proximity-based algorithm with a lepton-exclusion cone isolates neutron-induced depositions, improving sub-GeV direction reconstruction by about 20 degrees for antineutrinos.

Core claim

Traditional charge-based calorimetry is fundamentally limited at sub-GeV scales by recombination fluctuations and missing hadronic energy. Energy reconstruction using scintillation light partially benefits from the self-compensating light effect, and at neutrino energies above 400 MeV the light-only reconstruction outperforms charge-only methods that can separate EM and hadronic objects. Using the energy-deposit information from both detector signals achieves 70% efficiency in separating electron neutrinos and antineutrinos. By using a proximity-based algorithm coupled with a geometric lepton-exclusion cone, neutron-induced energy depositions can be isolated from background, enabling an ant

What carries the argument

The self-compensating light effect together with a proximity-based neutron isolation algorithm coupled to a geometric lepton-exclusion cone.

If this is right

Light-only reconstruction outperforms charge-only above 400 MeV while remaining comparable below 300 MeV.
Neutron isolation via proximity and exclusion cone sharpens antineutrino direction resolution by about 20 degrees.
Combined signals make neutrino-antineutrino separation feasible at sub-GeV energies.
The approach extends the physics capabilities of LArTPC atmospheric neutrino analyses.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

These reconstruction methods could be validated directly on existing LArTPC datasets to check real-world performance.
If the gains hold, they may improve sensitivity to low-energy oscillation parameters or atmospheric neutrino flux measurements.
The neutron isolation technique might extend to other interaction channels or detector technologies where neutral particles produce localized deposits.

Load-bearing premise

The self-compensating light effect and the proximity-based neutron isolation algorithm with lepton-exclusion cone will translate from simulation to real detector data without significant degradation from unmodeled effects such as impurities or field non-uniformities.

What would settle it

Applying the combined-signal separation and neutron-isolation methods to real LArTPC data and measuring a neutrino-antineutrino separation efficiency well below 70% or direction improvement much less than 20 degrees would falsify the performance claims.

Figures

Figures reproduced from arXiv: 2604.20957 by Ciro Riccio, Sanskar Jain, Stone Chou, Wei Shi.

**Figure 2.** Figure 2: FIG. 2. The distribution of deposited energy for the 1000 [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗

**Figure 3.** Figure 3: FIG. 3. Fraction of total available energy [PITH_FULL_IMAGE:figures/full_fig_p003_3.png] view at source ↗

**Figure 4.** Figure 4: FIG. 4. Calorimetric response distributions for the sample [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗

**Figure 5.** Figure 5: FIG. 5. Distributions of the reconstructed incident neutrino [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗

**Figure 7.** Figure 7: It shows that the resolution of the true available [PITH_FULL_IMAGE:figures/full_fig_p005_7.png] view at source ↗

**Figure 7.** Figure 7: FIG. 7. Resolution of the simulated true [PITH_FULL_IMAGE:figures/full_fig_p006_7.png] view at source ↗

**Figure 8.** Figure 8: FIG. 8. Scatter plot of the charge calorimetric responses [PITH_FULL_IMAGE:figures/full_fig_p006_8.png] view at source ↗

**Figure 9.** Figure 9: FIG. 9. Scatter plot of the light calorimetric responses of dif [PITH_FULL_IMAGE:figures/full_fig_p007_9.png] view at source ↗

**Figure 10.** Figure 10: FIG. 10. While the average charge recombination factor [PITH_FULL_IMAGE:figures/full_fig_p007_10.png] view at source ↗

**Figure 11.** Figure 11: FIG. 11. Resolution of the modified Q3 method – where pro [PITH_FULL_IMAGE:figures/full_fig_p008_11.png] view at source ↗

**Figure 13.** Figure 13: FIG. 13. A scatterplot of [PITH_FULL_IMAGE:figures/full_fig_p009_13.png] view at source ↗

**Figure 15.** Figure 15: FIG. 15. A scatterplot of [PITH_FULL_IMAGE:figures/full_fig_p010_15.png] view at source ↗

**Figure 16.** Figure 16: FIG. 16. Stacked distribution of the kinetic-energy fraction [PITH_FULL_IMAGE:figures/full_fig_p010_16.png] view at source ↗

**Figure 18.** Figure 18: FIG. 18. Schematic representation of the lepton exclusion [PITH_FULL_IMAGE:figures/full_fig_p011_18.png] view at source ↗

**Figure 17.** Figure 17: FIG. 17. Angular difference between the earliest and nearest [PITH_FULL_IMAGE:figures/full_fig_p011_17.png] view at source ↗

**Figure 19.** Figure 19: FIG. 19. Optimal lepton exclusion cone size, [PITH_FULL_IMAGE:figures/full_fig_p012_19.png] view at source ↗

**Figure 21.** Figure 21: FIG. 21. Angle difference between the reconstructed neutron [PITH_FULL_IMAGE:figures/full_fig_p013_21.png] view at source ↗

**Figure 23.** Figure 23: FIG. 23. Comparison of final correlation between neutron ki [PITH_FULL_IMAGE:figures/full_fig_p013_23.png] view at source ↗

**Figure 24.** Figure 24: FIG. 24. Angle difference between reconstructed neutrino di [PITH_FULL_IMAGE:figures/full_fig_p014_24.png] view at source ↗

**Figure 25.** Figure 25: FIG. 25. Neutrino direction reconstruction result with 1.5 [PITH_FULL_IMAGE:figures/full_fig_p014_25.png] view at source ↗

**Figure 26.** Figure 26: FIG. 26. Performance of neutrino direction reconstruction [PITH_FULL_IMAGE:figures/full_fig_p015_26.png] view at source ↗

read the original abstract

This paper presents a comprehensive study of the reconstruction of sub-GeV neutrino charged-current interactions within a Liquid Argon Time Projection Chamber (LArTPC). We demonstrate that traditional charge-based calorimetry is fundamentally limited at sub-GeV scales by significant recombination fluctuations and missing hadronic energy. We show that energy reconstruction using energy deposited as scintillation light (L) partially benefits from the previously reported self-compensating light effect. At neutrino energies above 400 MeV, the light-only reconstruction still outperforms charge-only methods that can separate EM and hadronic objects. The performance of the two remains comparable below 300 MeV. Using the energy-deposit information from both detector signals, we demonstrate a 70% efficiency in separating electron neutrinos and antineutrinos. By using a proximity-based algorithm coupled with a geometric lepton-exclusion cone, we also demonstrate the ability to isolate neutron-induced energy depositions from background. This enables an improvement of sub-GeV direction reconstruction by about 20 degrees for antineutrinos. This study provides new insights into how to enhance the physics reach of future LArTPC atmospheric neutrino analyses.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

This is a simulation-only study that applies charge-light complementarity and a neutron isolation algorithm to sub-GeV LArTPC events, reporting 70% nu/anti-nu separation and 20-degree angular gains, but without any real-data checks.

read the letter

The main takeaway is that the authors combine scintillation light with charge signals to address recombination losses and missing hadronic energy in sub-GeV charged-current interactions. They report a 70% efficiency for separating electron neutrinos from antineutrinos and show that a proximity-based neutron tag with a lepton-exclusion cone improves direction resolution by about 20 degrees for antineutrinos. They also note that light-only reconstruction starts to beat charge-only above roughly 400 MeV while the two are comparable below 300 MeV. These are concrete numbers for an energy range that matters for atmospheric neutrino oscillation work, and the neutron isolation step is a practical addition on top of earlier self-compensating light studies. The paper does a clear job laying out why standard charge calorimetry struggles at these scales and why the combined approach helps in simulation. The crossover energies and the specific algorithm details give readers something they can try to implement or test. The soft spots are straightforward. All results are Monte Carlo only, with no control samples or comparisons to actual detector data. Effects like impurities, space-charge distortions, field non-uniformities, and reconstruction inefficiencies are not quantified, so it is unclear how much the quoted 70% and 20-degree figures would shrink in practice. The abstract gives the headline numbers without error bars, baseline tables, or selection cuts, which makes it hard to judge robustness. The algorithm has tunable parameters such as cone angle and proximity threshold, raising the usual question of how much the performance depends on tuning to the simulated sample. This work is aimed at experimentalists doing reconstruction for LArTPC neutrino detectors, especially those focused on low-energy atmospheric analyses. Readers looking for incremental ideas on light-charge fusion and neutron tagging will find usable details, but anyone planning to rely on the performance claims will need more validation. I would send it to peer review. The methods are described enough to be examined, the topic is relevant, and referees can push on the simulation-to-data gap and demand clearer baselines.

Referee Report

2 major / 1 minor

Summary. This paper presents a simulation-based study of sub-GeV neutrino charged-current interactions in LArTPCs. It argues that charge-based calorimetry is limited by recombination fluctuations and missing hadronic energy, that scintillation light reconstruction benefits from a self-compensating effect and outperforms charge-only methods above 400 MeV, and that combined charge+light information yields 70% efficiency for separating electron neutrinos from antineutrinos. A proximity-based neutron isolation algorithm using a lepton-exclusion cone is shown to improve sub-GeV direction reconstruction by ~20° for antineutrinos, with the goal of enhancing future atmospheric neutrino analyses.

Significance. If the reported simulation improvements prove robust, the combined calorimetry and neutron-tagging techniques could meaningfully advance energy and angular resolution for low-energy neutrinos in LArTPCs, thereby increasing the reach of oscillation and atmospheric neutrino measurements in experiments such as DUNE.

major comments (2)

[Abstract] Abstract: The headline quantitative claims (70% νe/ν̄e separation efficiency and ~20° direction improvement) are stated without error bars, baseline comparisons to standard reconstruction, Monte Carlo details, or selection criteria, preventing assessment of whether the enhancements are statistically significant or method-dependent.
[Neutron isolation algorithm] Neutron isolation algorithm: The proximity-based tagging with lepton-exclusion cone depends on tunable parameters (cone angle and proximity threshold) whose optimization is not shown to be stable against unmodeled LArTPC effects such as impurities, space-charge distortions, or field non-uniformities; because the central claim is an enhancement applicable to real data analyses, this omission is load-bearing.

minor comments (1)

[Abstract] The abstract refers to the 'previously reported self-compensating light effect' without providing a citation to the original literature.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful and constructive review of our manuscript. The comments highlight important areas for improving clarity and robustness, and we address each major point below with plans for revision.

read point-by-point responses

Referee: [Abstract] Abstract: The headline quantitative claims (70% νe/ν̄e separation efficiency and ~20° direction improvement) are stated without error bars, baseline comparisons to standard reconstruction, Monte Carlo details, or selection criteria, preventing assessment of whether the enhancements are statistically significant or method-dependent.

Authors: We agree that the abstract would benefit from greater context to support the quantitative claims. In the revised manuscript, we will update the abstract to report statistical uncertainties on the 70% νe/ν̄e separation efficiency and the ~20° direction improvement, include brief descriptions of the Monte Carlo simulation details (e.g., event generator and sample size), outline the key selection criteria, and add explicit comparisons to standard charge-only reconstruction baselines. These changes will enable readers to better evaluate statistical significance and method dependence. revision: yes
Referee: [Neutron isolation algorithm] Neutron isolation algorithm: The proximity-based tagging with lepton-exclusion cone depends on tunable parameters (cone angle and proximity threshold) whose optimization is not shown to be stable against unmodeled LArTPC effects such as impurities, space-charge distortions, or field non-uniformities; because the central claim is an enhancement applicable to real data analyses, this omission is load-bearing.

Authors: The parameters of the proximity-based neutron isolation algorithm, including the lepton-exclusion cone angle and proximity threshold, were optimized within our idealized simulation framework to achieve the reported improvement in direction reconstruction. In the revised manuscript, we will add a dedicated subsection detailing the optimization procedure and demonstrating the stability of the ~20° improvement against reasonable variations in these parameters. Our study is performed in simulation without full modeling of real LArTPC effects such as impurities, space-charge distortions, or field non-uniformities; we will explicitly note this as a limitation of the current work and identify a more complete detector simulation incorporating these effects as a direction for future studies. This maintains the paper's focus on establishing the algorithmic potential while acknowledging the path to real-data applicability. revision: partial

Circularity Check

0 steps flagged

No significant circularity; reconstruction metrics are direct simulation outputs

full rationale

The paper evaluates distinct reconstruction algorithms (charge-only calorimetry, light-only using the self-compensating effect, combined charge+light, and proximity-based neutron isolation with lepton-exclusion cone) on Monte Carlo samples of sub-GeV neutrino interactions. Performance figures such as 70% νe/ν̄e separation efficiency and ~20° angular improvement are reported as direct results of applying these methods to simulated energy deposits, without any reduction by construction to fitted parameters, self-referential definitions, or load-bearing self-citations. The derivation chain consists of standard simulation-based comparisons that remain independent of the target metrics.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

Central claims rest on standard LArTPC detector response models, the previously reported self-compensating light effect, and simulation-tuned geometric parameters for the exclusion cone and proximity cuts; no new physical entities are introduced.

free parameters (2)

lepton-exclusion cone angle
Geometric parameter used to isolate neutron deposits; likely optimized on simulation data to achieve the reported direction improvement.
proximity threshold for neutron tagging
Distance-based cut in the isolation algorithm; value not specified but required for the 20-degree improvement claim.

axioms (2)

domain assumption Liquid argon charge and light response models including recombination fluctuations
Invoked to explain limitations of charge-only calorimetry at sub-GeV scales.
domain assumption Self-compensating light effect as previously reported
Used to argue that light-only reconstruction partially mitigates missing hadronic energy.

pith-pipeline@v0.9.0 · 5499 in / 1611 out tokens · 42298 ms · 2026-05-09T22:24:03.923764+00:00 · methodology

discussion (0)

Reference graph

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