NuGlass, an open-source web application described in a new arXiv preprint, turns three-flavor neutrino-oscillation calculations in constant-density matter into six linked, fully interactive 3D views. The application is backed by two independently implemented physics engines that were cross-validated against one another.
The main quantitative result is a software validation check, not a new neutrino measurement. The two engines were tested on 42,000 parameter points, with all nine flavor-channel probabilities compared at each point, for 378,000 comparisons in total. The largest absolute difference was 2.3 × 10⁻⁷ at the application’s default NNewton = 1 setting. Raising the refinement count to NNewton = 2 reduced that maximum difference to 2.3 × 10⁻¹⁰. No confidence intervals or inferential uncertainty estimates were reported.
Two engines, one set of controls
NuGlass derives its quantitative visual displays from calculated complex flavor amplitudes and oscillation probabilities. That lets the application present both the probabilities themselves and the amplitude-level calculations behind several of its views.
The two engines have different computational roles. One is a line-by-line JavaScript port of NuFast-LBL and calculates probabilities. The other uses a complex-Hamiltonian cyclic Jacobi eigensolver for amplitude-level calculations. The validation compares their probability results across the same parameter grid.
All six views share a reactive parameter store, the selected oscillation channel, experiment presets and common interactions. A change in the shared controls can therefore be examined through linked representations of the same calculation.
What the visual examples show
In the illustrated Statesphere example, the tau-mu arrow follows a near-great-circle path, while the electron-muon arrow stays near the sphere’s center. The electron-muon arrow has a length of 0.17. At the marked point, the probabilities are 0.049 for electron flavor, 0.120 for muon flavor and 0.831 for tau flavor. These figures describe one selected numerical example rather than a statistical estimate.
The Phasors view presents interference through complex contributions. At a stated DUNE-like parameter point, the muon-to-tau channel is shown as an approximately two-phasor system in matter because the middle arm is much smaller than the two outer arms. The reported arm magnitudes are 0.497, 0.018 and 0.481, with the middle arm reduced by about a factor of 25 relative to its neighbors.
The Statesphere and phasor results are selected numerical demonstrations at particular parameter points. They show the kinds of structure the application is designed to display, but they are not independent empirical tests.
A useful but narrow model
NuGlass is a single-page, fully client-side application with no backend. It uses Vue 3, three.js and WebGL, together with Canvas 2D, and its full bundle is approximately 190 kB gzipped.
The reported performance varies with the animation path and with whether geometry must be rebuilt. Cached-geometry animations sustained 45 to 60 frames per second, while the oscillogram δCP sweep ran at roughly 20 frames per second and the Flavortube L sweep at roughly 12 frames per second.
The engines assume constant matter density. Inverted ordering is approximated by flipping the sign of the atmospheric mass splitting while retaining normal-ordering best-fit magnitudes. The model therefore does not represent a full inverted-ordering parameter set or variable-density propagation.
The application intentionally omits fluxes, cross sections, detector resolutions and statistical uncertainties. It visualizes oscillation probabilities only, so its scope is narrower than a complete experimental analysis.
Built for research, teaching and outreach
The author describes NuGlass as a research companion, teaching instrument and outreach exhibit. The application was developed through an issue-based human-AI collaboration cycle with a coding agent.
The work is supported by the US Department of Energy Office of Science, Office of High Energy Physics under Contract No. DE-SC0012704. The front matter identifies the manuscript as arXiv:2608.25049v1, dated 25 August 2026, and says it was prepared for submission to JINST.
The application is deployed at https://czczc.github.io/nuglass/. The source, issue tracker and citation metadata are available through https://github.com/czczc/nuglass/.
Paper data and sources
Original title: NuGlass: A Fast and Interactive 3D Visualization of Neutrino Oscillations
Authors: Chao Zhang
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-25
DOI: Not available
Original paper · Full text