'Pentaquark' hints at answers to matter

OSAKA, Japan — Physicists have discovered a new class of subatomic particles, offering unexpected insights into the building blocks of matter.

The discovery, published in Physical Review Letters, involves tiny particles called "quarks," the bricks and mortar of protons and neutrons in the atomic nucleus.

Until now, physicists had only seen quarks packed into two- or three-quark combinations inside the larger subatomic particles.

These combinations have always been something of a mystery, but a Japanese team led by Takashi Nakano of Osaka University said it has created a five-quark particle, "a pentaquark."

"Determining why the pentaquark appeared in the experiment should offer great insight into the nature and stability of the essential building blocks of all matter," physicist Ken Hicks of Ohio University in Athens, Ohio, who took part in both the experiment and a confirmatory effort, told USA Today.