A mile below the rolling hills of South Dakota, in a cavern blasted out of a former gold mine, the largest neutrino experiment ever attempted is taking shape. The Deep Underground Neutrino Experiment, or DUNE, is being built to answer a question that physics has stared at for decades without a clear answer: why is there anything at all?
In May 2026, officials and partners gathered in Lead, South Dakota, to mark a structural milestone — the start of moving 4.5 million kilograms of steel beams underground to hold the detectors in place. The event was attended by senior figures including CERN’s director-general. The cavern is now ready to receive its instruments.
The matter problem
The Big Bang should have produced equal amounts of matter and antimatter. When matter and antimatter meet, they annihilate. In a perfectly symmetric universe, the result would have been almost pure radiation — no stars, no planets, no people.
But the universe is overwhelmingly matter. For every billion antiparticles that existed in the early universe, slightly more than a billion particles survived. The tiny excess is everything we see.
Something broke the symmetry. Physicists call it CP violation — a slight difference in how nature treats matter and antimatter. Some has been observed in quarks, but it isn’t enough. The leading candidate for the rest of the asymmetry: neutrinos.
How DUNE will test it
The plan is simple in concept. Fermilab, in Illinois, will produce the most intense neutrino beam ever built and fire it directly through the Earth toward South Dakota. The beam travels in a straight line through 1,300 kilometers of rock — neutrinos barely interact with anything, so the planet might as well not be there.
When the beam arrives at the Sanford Underground Research Facility in Lead, South Dakota, it will pass through DUNE’s far detector: four enormous tanks, each containing 17,000 tons of liquid argon, cooled to −186 °C. When a neutrino occasionally collides with an argon nucleus, the products of the collision ionize the liquid, and the path of the resulting particles is reconstructed in three dimensions — like a particle physics MRI.
Fermilab will run this experiment twice: once with a beam of muon neutrinos, once with a beam of muon antineutrinos. If neutrinos and antineutrinos oscillate at slightly different rates between Illinois and South Dakota, that difference is exactly the CP violation physicists are looking for.
Why liquid argon
Other neutrino detectors use water or scintillator. DUNE chose liquid argon for three reasons.
First, resolution. A liquid-argon time-projection chamber records the trajectory of every charged particle in fine detail, allowing the experiment to identify neutrino interactions by their full event topology rather than a handful of light flashes.
Second, mass density. A kiloton of argon contains far more interaction targets than a kiloton of water, given the same physical volume.
Third, a strong neutrino-argon cross-section in the relevant energy range. Argon is heavy enough to give DUNE a decent rate of interactions without needing an absurdly intense beam.
The combination is what makes DUNE unique. No other neutrino experiment will look at events with quite this fidelity.
What else DUNE could find
CP violation is the headline goal. But the detector is sensitive to other physics that won’t fit easily into one paragraph.
DUNE will watch for supernova neutrinos. If a star explodes anywhere in our galaxy during the experiment’s lifetime, DUNE expects to record several thousand events — enough to map the time profile of the collapse and learn about the new neutron star or black hole as it forms. (See our piece on SN 1987A for what 24 such events did in 1987.)
It will look for proton decay, a long-predicted but never-observed process that would confirm grand unified theories.
It will hunt for sterile neutrinos, non-standard interactions, and other extensions of the Standard Model.
And it will refine measurements of neutrino oscillation parameters, including the mass ordering — whether the three known neutrinos are arranged “normally” (one heavy, two light) or “inverted” (two heavy, one light).
Timeline
The far-detector caverns are excavated. The cryostat structures are being installed through 2026 and 2027. Filling the first cryostat with liquid argon and beginning early data-taking is planned for around 2028. The neutrino beam from Fermilab — and with it, the full physics program — is expected to start operations later in the decade.
If everything works as designed, DUNE will be taking measurements through the 2030s and into the 2040s. Like IceCube, it is built as a generation-spanning instrument.
Why this matters
The question of why matter exists is one of the few open problems in physics that genuinely touches everything. If CP violation in the neutrino sector turns out to be the missing piece, the story of the early universe will be partially rewritten by the time DUNE files its first big result.
The cavern under Lead, South Dakota was once dug by miners hunting for gold. The next thing it produces could be considerably more valuable.
Further reading
Primary sources
- Abi et al. (DUNE), “Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume I”, JINST 15:T08008 (2020)
- DUNE collaboration, “Long-baseline neutrino oscillation physics potential of the DUNE experiment”, Eur. Phys. J. C 80:978 (2020)
- DUNE collaboration, “Snowmass Neutrino Frontier: DUNE Physics Summary”, 2022 — community planning document
Background and context
- DUNE official site (Fermilab) — international collaboration homepage
- Sanford Underground Research Facility — host laboratory in Lead, SD
- Wikipedia: Deep Underground Neutrino Experiment
- Fermilab — LBNF/DUNE construction updates — official LBNF facility status
Frequently asked
What is DUNE?
DUNE — the Deep Underground Neutrino Experiment — is a long-baseline neutrino experiment under construction in the United States. It will fire a beam of muon neutrinos from Fermilab through 1,300 kilometers of Earth to a 70-kiloton liquid argon detector at the Sanford Underground Research Facility in South Dakota. The goal is to measure CP violation, the mass ordering, and search for proton decay and supernova neutrinos.
What is DUNE measuring?
Primarily the CP-violating phase δ_CP and the neutrino mass ordering, by comparing how muon neutrinos and muon antineutrinos appear as electron neutrinos at the far detector. The long baseline produces significant matter effects, giving DUNE direct sensitivity to the mass ordering. Other goals include precision oscillation parameter measurements, supernova-burst detection, and proton-decay searches.
Why liquid argon?
Liquid argon time projection chambers provide millimeter-scale three-dimensional imaging of each neutrino interaction, with excellent particle identification. The technology allows DUNE to distinguish electron neutrinos from photon-induced backgrounds event by event — critical for the CP-violation measurement.
When will DUNE produce results?
First beam from Fermilab's upgraded LBNF beamline is expected in the late 2020s. DUNE's full four-module 70-kiloton configuration will accumulate data through the 2030s, with definitive measurements of CP violation and the mass ordering expected by the mid-2030s.
How does DUNE compare to Hyper-Kamiokande?
Both target CP violation and the mass ordering, but with different strategies. DUNE has a longer baseline (1,300 km vs 295 km) and uses liquid argon TPCs. Hyper-Kamiokande uses much larger water Cherenkov volumes. DUNE has direct mass-ordering sensitivity from matter effects; Hyper-K relies on combination with JUNO. The two experiments cross-check each other.
Cite this article 5 formats
APA
Neutrino Times Editorial Team. (2025, June 3). DUNE: the underground experiment that wants to know why matter exists. Neutrino Times. https://neutrino-times.com/articles/dune-underground-experiment-matter-mystery/
Chicago
Neutrino Times Editorial Team. "DUNE: the underground experiment that wants to know why matter exists." Neutrino Times, June 3, 2025. https://neutrino-times.com/articles/dune-underground-experiment-matter-mystery/.
MLA
Neutrino Times Editorial Team. "DUNE: the underground experiment that wants to know why matter exists." Neutrino Times, 3 Jun. 2025, https://neutrino-times.com/articles/dune-underground-experiment-matter-mystery/.
BibTeX
@misc{neutrino-times-dune-underground-experiment-matter-mystery,
author = {Neutrino Times Editorial Team},
title = {DUNE: the underground experiment that wants to know why matter exists},
howpublished = {Neutrino Times},
year = {2025},
month = {jun},
url = {https://neutrino-times.com/articles/dune-underground-experiment-matter-mystery/},
note = {Accessed: 2025-06-03}
} RIS
TY - GEN TI - DUNE: the underground experiment that wants to know why matter exists AU - Neutrino Times Editorial Team PY - 2025 DA - 2025-06-03 PB - Neutrino Times UR - https://neutrino-times.com/articles/dune-underground-experiment-matter-mystery/ ER -