Plate Nº 13 · recorded November 11, 2026
PhysicsReported finding
No 'quirks' at the LHC — but first FASER search tightens the net
FASER's first dedicated LHC quirk search found no sign of the hypothetical particles, but ruled out a broad mass range tied to the gauge hierarchy problem.
By Elena Vasquez4 min read747 words
In brief
- FASER analyzed LHC data from 2022–2024 and found no evidence of quirk pairs.
- The study was published in Physical Review Letters in 2026 (DOI: 10.1103/z156-xk5y).
- The weak nuclear force is about 10²⁴ times stronger than gravity — the gauge hierarchy problem quirks aim to explain.
- Quirks were proposed in 2008 by Markus Luty and Junhai Kang at the University of Maryland.
- FASER sits 480 m downstream of ATLAS behind over 100 m of rock.
After three years of data collection, physicists at the Large Hadron Collider have found no evidence for "quirks" — hypothetical heavy, slow-moving particles proposed to explain why gravity is so absurdly weak compared with the other fundamental forces. The FASER Collaboration published its first dedicated quirk search at the LHC in Physical Review Letters in 2026, and while the hunt came up empty, the analysis rules out a broad range of particle masses and could push other collider experiments to join the chase.
What are quirks, and why do physicists want them?
The Standard Model of particle physics remains the most reliable description of the universe's building blocks and their interactions, and it has survived every experimental test thrown at it. But physicists know it's incomplete. The most famous gap is dark matter. Another is stranger: the weak nuclear force is roughly 10²⁴ times stronger than gravity, a disparity physicists call the "gauge hierarchy problem." Nothing in the Standard Model explains it.
One proposed fix adds an entirely new gauge group — in plain terms, a new mathematical structure governing a new force — to the Standard Model. In 2008, building on ideas from the 1980s, Markus Luty and Junhai Kang at the University of Maryland proposed a family of hypothetical fundamental particles they named quirks. In some theories, quirks interact with the Higgs boson, the particle responsible for giving elementary particles their mass.
That interaction matters. It could stop quantum effects from pushing the Higgs boson's mass far above its observed value — and since gravity acts on mass rather than charge, the effect would ultimately keep gravity vastly weaker than the other three forces.
Central to the theory is a new force called "infracolor," which closely resembles the strong nuclear force that binds atomic nuclei.
How do you catch a particle nobody has seen?
Infracolor has a peculiar consequence. "This force could hold quirk-antiquirk pairs together with a nearly unbreakable string," said Eli Welch of the University of California, Irvine, primary author of the new analysis. "This would cause them to oscillate as they travel and make them difficult to simulate and detect."
If quirks exist, physicists predict high-energy collisions could produce them in pairs, leaving distinctive traces in detectors. The trouble is finding those traces.
The first dedicated quirk search ran in 2010 at Fermilab's Tevatron collider. At the LHC, several of its nine detection experiments are sensitive to quirks, but those searches have depended either on tracing particle paths — nearly hopeless given quirks' complex oscillating trajectories — or on spotting quirks that stop and annihilate inside the detector.
What makes FASER different?
FASER, the Forward Search Experiment, sits 480 meters (1,575 feet) downstream of the ATLAS experiment, shielded by more than 100 meters (328 feet) of rock. It was built to detect neutrinos created in particle collisions and to hunt for new elementary particles. The rock shielding means very few background particles reach it — ideal conditions for spotting pairs of heavy quirks passing through.
The method is the real innovation. "By measuring their delayed arrival and slow speed, together with the unusually large energy deposits from both particles, we can identify quirks without having to trace their paths," Welch explained. "This makes our search far less sensitive to their unusual oscillations than conventional searches."
What did the search find?
Nothing — and that's still progress. The collaboration analyzed data collected between 2022 and 2024, looking specifically for a quirk signal, and detected no evidence of the pairs it was after.
Even so, the null result carries weight. "Our results rule out a broad range of possibilities within the quirk model we considered, including masses of particular interest to theories of physics beyond the Standard Model," Welch said.
The paper is credited to Roshan Mammen Abraham et al., "First Search for Quirks at the LHC with FASER," Physical Review Letters (2026), DOI: 10.1103/z156-xk5y.
Where does the search go from here?
The collaboration hopes its initial results lay groundwork for an expanded quirk search at the LHC. By demonstrating that the particles' odd behavior can be detected without conventional tracking methods, FASER may motivate other collider experiments to take up the hunt.
"More broadly, it highlights the importance of looking beyond conventional particle signatures, as new physics could be hiding in signals that existing searches were not designed to detect," Welch added.
One takeaway: quirks remain unproven and, for now, unobserved — but the search space just got measurably smaller.
via phys.org/rss-feed/ (Source)
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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