BY:SpaceEyeNews.
CERN primordial plasma research has pushed one of particle physics’ most important boundaries. Scientists found strong evidence that oxygen-16 and neon-20 collisions can create tiny droplets with the collective behavior of quark-gluon plasma. Researchers once relied mainly on far heavier lead nuclei to produce clear plasma signatures. The new results show that much smaller systems can display the same fluid-like response.
Collisions of spherical oxygen nuclei produce a relatively round trace.
CERN Primordial Plasma Emerges From Light Nuclei
The Large Hadron Collider conducted a special light-ion campaign in July 2025. It brought oxygen nuclei together with oxygen and neon nuclei with neon. Each collision reached a center-of-mass energy of 5.36 teraelectronvolts per nucleon pair.
These events created extreme temperatures and pressures on a microscopic scale. For a fleeting moment, quarks and gluons could move through a hot, dense medium instead of remaining confined inside protons and neutrons. Such conditions resemble those found during the Universe’s first millionths of a second.
The experiment did not recreate the early Universe as a whole. It created femtoscale droplets that rapidly expanded, cooled, and converted into ordinary particles.
This matters because scientists have debated how small a system can become while still supporting plasma-like collective motion. Oxygen-16 contains 16 nucleons, while neon-20 contains 20. Both are much smaller than lead-208. Yet they have better-understood structures than a proton. That combination gave physicists a more controlled test of whether hydrodynamic behavior can emerge in light collision systems.
Physical Review Letters published the peer-reviewed ALICE study on August 17, 2026, as an Editors’ Suggestion.
How ALICE Read a Plasma That Vanished Instantly
The ALICE detector could not photograph the plasma directly. Instead, researchers reconstructed its behavior from the charged particles that reached the detector after each event.
The team focused on two measurements called elliptic flow and triangular flow. Physicists label them v2 and v3. These values describe how strongly particles prefer certain directions around the collision point. Random particle production would not generate the same coordinated patterns across enormous data samples.
Particle Flow Carried the Hidden Evidence
ALICE detected sizable elliptic and triangular flow in both oxygen-oxygen and neon-neon events. The values also changed with collision centrality.
Researchers then compared the measurements with advanced hydrodynamic models. The calculations included realistic descriptions of the oxygen and neon nuclei. They successfully reproduced the main magnitudes and trends in the data. According to ALICE, the agreement matched or surpassed the accuracy achieved in much larger heavy-ion systems.
The result supports nuclear-geometry-driven hydrodynamic flow in light-ion collisions. It therefore strengthens the case that these events created femtoscale droplets of quark-gluon plasma. Scientists detected the plasma through its effects; they did not observe the droplet itself.
CERN has also reported several additional plasma indicators from light-ion experiments. These include energy loss by fast partons moving through the hot medium and the suppression of energetic particle production. Results from ALICE, ATLAS, CMS, and LHCb now provide complementary evidence that oxygen and neon collisions can produce this extreme state of matter.
Neon’s Shape Left a Measurable Signature
Particle flow also revealed nuclear geometry.
Oxygen-16 has a comparatively rounded structure. Neon-20 has a more elongated form that researchers often compare to a bowling pin. When these nuclei meet, their shapes influence the initial outline of the hot medium. Pressure inside that medium then converts the spatial asymmetry into differences in particle momentum.
Why Neon Produced Stronger Elliptic Flow
Central neon-neon collisions showed greater elliptic flow than central oxygen-oxygen collisions. Hydrodynamic models predicted this difference when they included the nuclei’s intrinsic structures. The surviving flow pattern therefore carried information from the collision’s earliest stage.
The popular “shadow” analogy helps explain the method. A shadow can reveal an object’s shape even when the object remains hidden. Likewise, outgoing particles reveal aspects of the original nuclear geometry after the plasma has disappeared.
However, a detector does not record a literal bowling-pin outline during one event. The conclusion comes from statistical correlations across vast numbers of collisions. Comparing neon and oxygen flow ratios also reduces some uncertainties from the plasma’s later development. That makes the results more sensitive to nuclear deformation and smaller-scale structure.
Why CERN Primordial Plasma Changes Nuclear Physics
The discovery connects two areas that scientists often study separately. First, it narrows the gap between large lead-ion experiments and much smaller proton-based systems. Proton-proton collisions have shown collective patterns, but their interpretation remains difficult because the proton’s internal geometry carries major uncertainties. Oxygen and neon provide a cleaner middle ground.
Second, the method could open a new route for studying atomic nuclei. Researchers traditionally examine nuclear rotations, vibrations, and energy levels at relatively low energies. At the LHC, they can now collide nuclei at extreme energies and reconstruct their geometry from the particles left behind.
Better nuclear-shape measurements could clarify how protons and neutrons organize themselves. They may also improve models of the strong interaction, which quantum chromodynamics describes. More accurate starting geometries would help researchers calculate how quark-gluon plasma expands and how close it comes to behaving like a nearly perfect liquid.
Scientists still do not know the minimum system size needed to sustain this collective behavior. Researchers have proposed future tests with even lighter nuclei, including helium-4. Those experiments could show whether plasma-like motion continues or suddenly fades below a specific threshold.
CERN Primordial Plasma Opens a Smaller Frontier
CERN primordial plasma experiments now connect the structure of atomic nuclei with conditions from the Universe’s earliest moments. Oxygen and neon produced collective flow that modern hydrodynamic models describe with striking accuracy. Neon also left a stronger elliptic signature linked to its elongated shape.
The result does not reproduce the complete early cosmos, nor does it directly image primordial matter. Instead, it creates microscopic laboratories where particle patterns preserve traces of an otherwise invisible state. If helium produces similar behavior, physicists may need to move the boundary of quark-gluon plasma even further.
Main Sources:
CERN — Oxygen collisions at the LHC show new indications of extreme state of matter
https://home.cern/oxygen-collisions-at-the-lhc-show-new-indications-of-extreme-state-of-matter/
ALICE Collaboration — Geometry-driven flow in collisions of Oxygen and Neon ions at the LHC
https://alice-collaboration.web.cern.ch/2025-ALICE-Oxygen-Neon-Flow
Physical Review Letters — Evidence of Nuclear Geometry-Driven Anisotropic Flow in O+O and Ne+Ne Collisions
https://journals.aps.org/prl/abstract/10.1103/gymp-vp87
University of Copenhagen — Researchers create a Little Big Bang
https://science.ku.dk/english/press/news/2026/researchers-create-a-little-big-bang-bowling-pin-shaped-nuclei-shed-new-light-on-the-universes-first-moments/