Physicists analysing three years of data from the Large Hadron Collider have found no evidence of hypothetical heavy particles known as quirks, phys.org reported on November 10, 2026.
The Standard Model of particle physics successfully describes fundamental building blocks and interactions, yet it contains notable omissions. Researchers cannot explain the nature of dark matter or why the weak nuclear force remains roughly 10²⁴ times stronger than gravity. Markus Luty and Junhai Kang proposed quirks in 2008 to address this discrepancy, known as the gauge hierarchy problem.
Quirk-antiquirk pairs would theoretically interact via an infracolor force resembling the strong nuclear force. Eli Welch at the University of California, Irvine, explained that this force would hold pairs together with a nearly unbreakable string. That binding causes the particles to oscillate as they travel, complicating simulation and detection efforts.
Fermilab’s Tevatron hosted the first dedicated search for quirks in 2010. The recent analysis utilised the Forward Search Experiment (FASER) located 480 meters downstream of the ATLAS experiment. Shielded by over 100 meters of rock, FASER encounters minimal background particle interference.
Welch stated that researchers identified quirks without tracking paths by measuring delayed arrival, slow speed, and large energy deposits. The FASER Collaboration evaluated data collected between 2022 and 2024 to spot a quirk signal.
“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 explains.
The analysis ruled out a broad range of possibilities within the considered quirk model, including specific masses relevant to theories beyond the Standard Model. Welch noted that demonstrating detection without traditional tracking methods could motivate other collider experiments to join the search.
The FASER Collaboration published its findings in Physical Review Letters.
