Scientists discover heavier version of proton with upgraded detector | Particle physics

Scientists at the Cern nuclear physics laboratory near Geneva have discovered a heavier version of the proton, the subatomic particle at the heart of all known atoms in the universe.

They spotted the particle in a shower of debris that illuminated a detector at the Large Hadron Collider (LHC), located deep underground at Cern, which smashes protons together at close to the speed of light. The collisions recreate in a microcosm the conditions that prevailed just after the big bang, with energy converted into particles thrown in all directions.

The new particle, four times heavier than the ordinary proton, should help physicists refine their understanding of the strong nuclear force that binds the innards of all atomic nuclei. This force is unusual because it behaves like a rubber band, becoming stronger as the distance between subatomic particles increases.

Physicists working on the LHCb experiment discovered the heavy proton after the detector was upgraded to make it more powerful.

“This is just the first of many expected insights that can be obtained with the new LHCb detector,” said Professor Tim Gershon of the University of Warwick, who will take over as international director of LHCb in July. “The improved detection capability allowed us to find the particle after just a year, whereas we had not been able to see it in a decade of data collected with the original LHCb.”

Hydrogen atoms, the simplest and most abundant element in the observable universe, contain only one proton and one electron. Protons, as well as neutrons in heavier atoms, are made up of elementary subatomic particles called quarks. A proton contains two up quarks and one down quark, but there are heavier, unstable versions of quarks called charm, strange, top, and bottom.

In the heavy proton detected at CERN, the two up quarks are replaced by charmed quarks. The particle, named Xi-cc-plus, was revealed by its signature decay into other particles. After its appearance, it does not stay in place: scientists suspect that it survives for less than a millionth of a millionth of a second before collapsing.

“The more we learn about these particles, the more we can learn about the strong force, and it’s the same strong force that binds our protons and neutrons together,” said Professor Chris Parkes, a physicist at the University of Manchester.

The discovery comes as UK Research and Innovation (UKRI), the country’s science funder, faces intense criticism for plans to withdraw £50 million of funding for the LHCb’s final upgrade in the 2030s. The overhaul would allow the detector to make the most of a major transformation of the LHC that could significantly improve its discovery potential.

British scientists working in particle physics, astronomy and nuclear physics have been told their grants will be cut following cost overruns at key science facilities. Projects were also affected, including the upcoming LHCb upgrade and an electron-ion collider being developed with US researchers.

Last week, Chi Onwurah, chair of the Commons science committee, sent a scathing letter to Professor Ian Chapman, UKRI’s chief executive, and Patrick Vallance, science minister, calling the cuts “completely unacceptable” and a “failure” by UKRI, the Science and Technology Facilities Board and the Department of Science, Innovation and Technology.

The letter demands “rapid and decisive action” and asks whether the decision regarding the LHCb upgrade is final.

“It is very important that we can overcome the problems caused by UKRI’s decision not to prioritize funding for this project,” Gershon said. “No other experiments underway or planned will be able to achieve this physics.”