British scientists have played a central role in the discovery of a new subatomic particle at the Large Hadron Collider, marking a significant moment for UK science on the global stage.
Researchers supported by the Science and Technology Facilities Council, STFC, helped identify the particle, known as the Ξcc⁺, at CERN’s flagship accelerator near Geneva. The finding represents the first new particle discovered using the upgraded LHCb experiment, one of the collider’s major international projects.
The Ξcc⁺ is a heavier relative of the proton, a fundamental building block of matter. While a proton is composed of two up quarks and one down quark, the newly observed particle contains two charm quarks and one down quark, making it roughly four times heavier.
Understanding the building blocks of matter
Quarks are among the smallest known components of the universe, combining to form particles such as protons and neutrons, which sit at the heart of atoms. The most familiar types are up and down quarks, but heavier varieties, including charm quarks, also exist.
By studying how these quarks combine, scientists can deepen their understanding of the forces that govern matter. The Ξcc⁺ provides a rare opportunity to examine how heavier quarks behave when bound together.
A triumph for the upgraded LHCb experiment
The discovery was made possible by major upgrades to the LHCb detector, which now records far larger volumes of data than before. This enhanced capability allows researchers to observe extremely rare particle interactions that would previously have gone unnoticed.
The first full dataset from the upgraded system, collected in 2024, led directly to the identification of the Ξcc⁺. The particle was detected through its decay into three lighter particles during high energy proton collisions.
The result also resolves a long standing question in particle physics. A similar particle had been reported in the United States more than two decades ago, but the evidence was never confirmed until now.
British expertise at the heart of the project
The United Kingdom has made the largest national contribution to the upgraded LHCb detector. Teams from leading universities and laboratories across the country worked over more than a decade to design and build critical components.
Among the most important contributions is a highly precise silicon tracking system, known as the Vertex Locator, positioned just five millimetres from the particle beams. This detector enables scientists to pinpoint where particles are created and how they decay.
UK researchers also helped develop the Ring Imaging Cherenkov system, which identifies different particles by measuring the light they emit as they pass through specialised materials. This technology proved essential in confirming the identity of the Ξcc⁺.
Continuing a proud scientific legacy
The discovery has been hailed as a continuation of Britain’s long tradition of breakthroughs in particle physics. More than a century after Ernest Rutherford’s pioneering work on the structure of the atom in Manchester, UK scientists remain at the forefront of uncovering the universe’s most fundamental secrets.
Professor Chris Parkes of the University of Manchester, who led the international collaboration during the detector’s installation, said the achievement demonstrates both the power of modern technology and the strength of the UK’s contribution.
He noted that the upgraded detector has opened the door to discoveries that were previously beyond reach, allowing scientists to achieve in a single year what once required a decade of data.
Looking ahead to further discoveries
CERN’s leadership has described the result as a clear example of how continued investment in experimental upgrades can drive major scientific advances. The success of the LHCb upgrade is expected to pave the way for further discoveries as the collider moves towards its next phase, the High Luminosity LHC.
Professor Tim Gershon of the University of Warwick, who is set to lead the LHCb collaboration from July 2026, said the breakthrough signals a new era for the experiment. With vastly improved data collection, researchers are now poised to explore previously inaccessible areas of particle physics.
As the upgraded detector continues to gather data, scientists anticipate more insights into the fundamental structure of matter, reinforcing the United Kingdom’s position at the forefront of global scientific discovery.
Source: UKRI
Main Image: For illustration purposes only
