Physicists discover a heavy cousin of the proton at CERN’s Large Hadron Collider

Science News from research organizations Physicists discover a heavy cousin of the proton at CERN’s Large Hadron Collider CERN scientists have discovered a long-predicted heavy cousin of the proton, finally solving a 20-year mystery. Date: March 19, 2026 Source: University of Manchester Summary: A new subatomic particle known as the Ξcc⁺ has been discovered at CERN’s Large Hadron Collider. This heavy proton-like particle contains two charm quarks and was detected using the upgraded LHCb experiment. Scientists observed it through its decay into lighter particles in high-energy collisions. The finding confirms predictions and settles a decades-long question about its existence. Share: Facebook Twitter Pinterest LinkedIN Email FULL STORY Artist’s illustration of this heavy proton-like particle. Credit: Chris Parkes Scientists from The University of Manchester have played a key role in identifying a previously unknown subatomic particle at CERN's Large Hadron Collider (LHC). The particle, called the Ξcc⁺ (Xi-cc-plus), is a heavy proton-like particle made up of two charm quarks and one down quark. This marks the first particle discovery using the upgraded LHCb detector. The upgrade is part of a major international effort involving more than 1,000 researchers across 20 countries.

The United Kingdom contributed more than any other nation, with Manchester providing significant leadership. A Heavier Relative of the Proton The newly discovered Ξcc⁺ is part of the same family as the proton, which was first identified in Manchester by Ernest Rutherford and colleagues between 1917-1919. While a proton contains two up quarks and one down quark, the Ξcc⁺ replaces the up quarks with heavier charm quarks. This finding also builds on a long history of particle physics research at Manchester. In the 1950s, scientists at the university were the first to identify a member of the Ξ (Xi) particle family, laying the groundwork for discoveries like this one. Manchester's Role in the LHCb Detector Upgrade Professor Chris Parkes, head of the University's Department of Physics and Astronomy, led the international collaboration during the installation and early operation of the upgraded LHCb detector. He also oversaw the United Kingdom's involvement in the project for more than ten years, guiding it from initial approval through completion. The Manchester LHCb team designed and built essential parts of the upgraded tracking system, including silicon pixel detector modules assembled in the University's Schuster Building. These components are critical for accurately tracking particle decays and identifying signals such as the Ξcc⁺. Professor Parkes, said, "Rutherford's gold-foil experiment in a Manchester basement transformed our understanding of matter, and today's discovery builds on that legacy using state-of-the-art technology at CERN. Both milestones demonstrate just how far curiosity driven research can take us. This discovery showcases the extraordinary capability of the upgraded LHCb detector and the strength of UK and Manchester contributions to the experiment." Advanced Detector Captures Particle Collisions Dr.

Stefano De Capua from The University of Manchester led the production of the silicon detector modules. He described the detector as operating like a high-speed camera. "The detector is a form of 'camera' that images the particles produced at the LHC and takes photographs 40 million times per second. It utilises a custom-designed silicon chip that also has a variant for use in medical imaging applications." How the Ξcc⁺ Particle Was Identified Researchers detected the Ξcc⁺ by observing how it decays into three lighter particles (Λc⁺ K⁻ π⁺). These decay events were recorded during proton-proton collisions at the LHC in 2024, the first year the upgraded LHCb experiment ran at full capacity. A clear signal of about 915 events was measured at a mass of 3619.97 MeV/c2. This result matches predictions based on a previously discovered related particle, the Ξcc⁺⁺. Solving a Two-Decade Mystery in Particle Physics For more than 20 years, scientists had debated earlier claims that this particle had been observed, but those findings were never confirmed. The new measurement from LHCb places the particle at a mass that does not match the earlier claim but does agree with theoretical expectations based on its partner particle.

What Comes Next for CERN and Manchester Looking ahead, The University of Manchester will continue to play a leading role in the next phase of the LHC program, known as LHCb Upgrade 2. This upgrade will take advantage of the High-Luminosity LHC accelerator to gather more data and explore rare particles in greater detail. Details of the Ξcc⁺ discovery are presented at the Rencontres de Moriond Electroweak conference. RELATED TOPICS Matter & Energy Quantum Physics Medical Technology Physics Detectors Telecommunications Nanotechnology Engineering and Construction Materials Science RELATED TERMS Particle physics Quark Introduction to quantum mechanics Proton Science Subatomic particle Schrödinger's cat Potential energy Story Source: Materials provided by University of Manchester. Note: Content may be edited for style and length.

Cite This Page: MLA APA Chicago University of Manchester. "Physicists discover a heavy cousin of the proton at CERN’s Large Hadron Collider." ScienceDaily. ScienceDaily, 19 March 2026. . University of Manchester. (2026, March 19). Physicists discover a heavy cousin of the proton at CERN’s Large Hadron Collider. ScienceDaily. Retrieved March 19, 2026 from www.sciencedaily.com/releases/2026/03/260319005106.htm University of Manchester. "Physicists discover a heavy cousin of the proton at CERN’s Large Hadron Collider." ScienceDaily. www.sciencedaily.com/releases/2026/03/260319005106.htm (accessed March 19, 2026). Explore More from ScienceDaily RELATED STORIES Large Hadron Collider Finally Explains How Fragile Matter Forms Dec. 27, 2025 — In collisions at CERN’s Large Hadron Collider, hotter than the Sun’s core by a staggering margin, scientists have finally solved a long-standing mystery: how delicate particles like deuterons and ...

Building Electronics That Don’t Die: Columbia's Breakthrough at CERN July 29, 2025 — Deep beneath the Swiss-French border, the Large Hadron Collider unleashes staggering amounts of energy and radiation—enough to fry most electronics. Enter a team of Columbia engineers, who built ... 'Spooky Action' at a Very Short Distance: Scientists Map out Quantum Entanglement in Protons Dec. 2, 2024 — Scientists have a new way to use data from high-energy particle smashups to peer inside protons. Their approach uses quantum information science to map out how particle tracks streaming from ... First Measurement of Electron And Muon-Neutrino Interaction Rates at the Highest Energy Ever Detected from an Artificial Source Aug. 5, 2024 — Understanding neutrino interactions is crucial for obtaining a complete picture of particle physics and the universe. To date, neutrino interaction cross sections have not been measured at high ...

Calculation Shows Why Heavy Quarks Get Caught Up in the Flow June 7, 2023 — Theorists have calculated how quickly a melted soup of quarks and gluons -- the building blocks of protons and neutrons -- transfers its momentum to heavy quarks. The calculation will help explain ... First Detection of Neutrinos Made at a Particle Collider Mar. 20, 2023 — A team including physicists has for the first time detected subatomic particles called neutrinos created by a particle collider, namely at CERN's Large Hadron Collider (LHC). The discovery ... TRENDING AT SCITECHDAILY.com Extreme Weather Is Shrinking Baby Birds in a 60-Year Study Deep Ocean Microbes May Already Be Adapting to Climate Change Something Strange Is Happening Deep Inside Greenland’s Ice Sheet Scientists Discover Surprising Eye Benefit of Widely Used Diabetes Drug