Physicists from the LHCb collaboration at CERN’s Large Hadron Collider (LHC) have detected the elusive Ωcc⁺ baryons. These particles, comprising two charm quarks and one strange quark, complete the long-sought family of doubly attractive baryons first predicted over half a century ago.
Artist’s impression of the Ωcc⁺ baryon, showcasing its dual charm. Image credit: Daniel Dominguez / CERN.
“Quarks are the essential building blocks of matter,” stated Dr. Paula Collins, deputy spokesperson for the LHCb collaboration.
“There are six types of quarks: up, down, charm, strange, top, and bottom. These quarks combine into pairs or triplets known as mesons and baryons, respectively.”
“Sixty years ago, researchers began uncovering the quark structure of matter, leading to the development of theoretical models that classify how quarks form composite particles.”
“These models allowed scientists to predict the properties of particles yet to be discovered.”
“The discovery of a new particle at Brookhaven National Laboratory in 1964 marked a pivotal moment.”
“This particle, composed of three strange quarks, was anticipated by theorists, and its experimental validation underscored the robustness of these theoretical frameworks.”
“The revelation of the fourth quark, the charm quark, in 1974 significantly impacted particle physics,” the researchers added.
“This advancement necessitated the extension of models to incorporate numerous new quark combinations.”
“Predictions included baryons with dual charm properties.”
“These baryons are made up of two charm quarks and a third quark, which could be up, down, or strange.”
“Physicists are particularly intrigued by this category of particles, as large mass differences between quarks can offer valuable insights into the strong forces that bind quarks into composite structures.”
“Despite these scientific interests, earlier experiments could not produce baryons with dual charms, and there were no sensitive instruments to detect them.”
Reconstruction of the Ωcc⁺ baryons produced and detected in the LHCb experiment. Image credit: CERN.
The LHCb physicists first discovered these dual-charm baryons in 2017, with the second discovery occurring earlier this year.
The discovery of the Ωcc⁺ represents the third and final member of this particle family. Based on data collected from high-energy proton-proton collisions at the LHC in 2024, new doubly attractive baryons were produced.
These baryons are ephemeral, traveling only a few millimeters through the detector before decaying into more stable particles.
The LHCb team traced the trajectories of these particles back to their origin, unveiling the distinctive signature of a new short-lived particle with a mass nearly four times that of a proton.
“This marks a beautiful and historically significant moment,” said Dr. Collins.
“Among the 85 composite particles discovered to date at the LHC, these three dual-charm baryons stand out as unique.”
“They decay under weak forces and have lifetimes long enough to yield measurable flight distances in our experiments.”
“This groundbreaking discovery was enabled by the upgraded detectors at LHCb, which possess advanced capabilities to track and identify particles.”
Source: www.sci.news