Scientists discover heavier version of proton with upgraded detector
CERN scientists have identified a heavier proton, dubbed Xi-cc-plus, in data from an upgraded LHCb detector. The particle, four times heavier than a normal proton, contains two charm quarks and provides a fresh window into the strong nuclear force. The discovery also highlights funding tensions for…
In a breakthrough announced by CERN, researchers have detected a heavier version of the proton, named Xi-cc-plus, using the upgraded LHCb detector at the Large Hadron Collider (LHC). The particle, which is roughly four times heavier than a standard proton, contains two charm quarks in place of the usual up quarks, offering a new probe into the strong nuclear force that binds atomic nuclei together.
How the discovery came about
The LHCb experiment, one of the four main detectors at CERN’s LHC, was recently upgraded to increase its sensitivity to rare and short‑lived particles. The new detector configuration allowed scientists to sift through the enormous amount of data produced by proton‑proton collisions at nearly the speed of light. In a shower of debris that lit up the detector, the Xi-cc-plus particle was identified through its characteristic decay pattern into other known particles.
Professor Tim Gershon of the University of Warwick, who took over as the international lead for LHCb in July, noted that the improved detection capability enabled the team to spot the Xi-cc-plus after just one year of data collection. In contrast, the original LHCb detector, operating for a decade, had not seen the particle.
What makes Xi-cc-plus special
Protons are composed of two up quarks and one down quark. The Xi-cc-plus replaces the two up quarks with heavier charm quarks, creating a particle that is unstable and decays in less than a millionth of a millionth of a second. This fleeting existence makes it a valuable laboratory for studying the strong force, which behaves like a rubber band that actually gets stronger as particles move apart.
Professor Chris Parkes of the University of Manchester emphasized that each new particle discovered adds to our understanding of the strong interaction, the same force that holds the protons and neutrons inside atomic nuclei together. The Xi-cc-plus provides a unique test case because its quark composition is rare and its mass is significantly higher than that of ordinary protons.
Implications for future research and funding
The discovery arrives amid growing criticism of the UK’s research funding body, UK Research and Innovation (UKRI), over planned cuts to the LHCb’s final upgrade in the 2030s. The upgrade is expected to enhance the detector’s capabilities in line with a major transformation of the LHC itself, potentially boosting the experiment’s discovery potential.
UK scientists across particle physics, astronomy, and nuclear physics have warned that funding reductions could jeopardise not only the LHCb upgrade but also other projects, such as an electron‑ion collider under development with U.S. partners. In a recent letter, Chi Onwurah, chair of the Commons science committee, called the cuts “wholly unacceptable” and demanded swift action to reverse the decision.
Professor Gershon highlighted the importance of maintaining support for LHCb, stating that no other experiment, current or planned, could achieve the same physics goals without the upgraded detector.
What’s next for the Xi-cc-plus
With the particle now confirmed, researchers will focus on measuring its properties more precisely, such as its lifetime, mass, and decay channels. These measurements will test predictions from quantum chromodynamics, the theory that describes the strong force. Additionally, the upgraded LHCb will search for other exotic states, including particles with different quark combinations or even entirely new forms of matter.
Meanwhile, the debate over funding for the LHCb upgrade continues. The scientific community remains hopeful that the UK’s political and financial commitments will be restored, ensuring that the experiment can fully exploit the LHC’s future upgrades and continue to push the boundaries of particle physics.
In summary, the discovery of the Xi-cc-plus not only adds a new member to the family of known particles but also underscores the critical role of advanced detectors and sustained funding in unlocking the mysteries of the subatomic world.
Why it matters
The Xi-cc-plus offers a fresh window into the strong force, a fundamental interaction that governs the stability of matter, while the discovery highlights the importance of continued investment in high‑energy physics experiments.
Key points
- CERN’s upgraded LHCb detector spotted the heavier proton Xi-cc-plus.
- Xi-cc-plus contains two charm quarks, making it four times heavier than a normal proton.
- The discovery helps refine our understanding of the strong nuclear force.
- UKRI funding cuts threaten the LHCb’s planned 2030s upgrade and other projects.
- Scientists plan to measure Xi-cc-plus properties to test quantum chromodynamics.
