The LHCb experiment at CERN’s Large Hadron Collider has reported the discovery of a class of particles known as pentaquarks. Formed by five quarks, the new particles will allow a better understanding how matter is put together.
Protons and neutrons – the building blocks of atomic nuclei – are composed of fundamental particles called quarks, which come in six different types. While a single quark is never observed in isolation, different arrangements of quarks make up protons, neutrons and other composite particles. Both protons and neutrons are formed by three quarks, the difference between a proton and a neutron being in the types of constituent quarks.
Their discovery was made possible by the Large Hadron Collider (LHC) at CERN, which accelerates particles at huge speeds and smashes them in very high energy collisions
“The pentaquark is not just any new particle,” said LHCb spokesperson Guy Wilkinson. “It represents a way to aggregate quarks, namely the fundamental constituents of ordinary protons and neutrons, in a pattern that has never been observed before in over fifty years of experimental searches.”
Pentaquarks had been previously theorized, and previous high energy physics experiments claimed to have observed pentaquarks, but the CERN experiment appears to be the first clear observation.
“The quarks could be tightly bound,” said LHCb physicist Liming Zhang of Tsinghua University, “or they could be loosely bound in a sort of meson-baryon molecule, in which the meson and baryon feel a residual strong force similar to the one binding protons and neutrons to form nuclei.” More studies are planned to distinguish between these possibilities.
Studying its properties may allow us to understand better how ordinary matter, the protons and neutrons from which we’re all made, is constituted. Also, new discoveries in fundamental physics often result in practical applications to energy, electronics and new materials.