In the course of exploring the properties of a strange subatomic particle, physicists may have stumbled upon something even stranger: a mysterious and exotic new form of matter.
The intriguing discovery was made more or less simultaneously by two collaborations: the Belle experiment at the Japanese High Energy Accelerator Research Organization (KEK) and BESIII experiment run by the Institute of High Energy Physics (IHEP) in China.
Both teams were looking at a particle called Y(4260) that had been discovered in 2005 but whose nature has mystified researchers since. By smashing together electrons and their antiparticle, positrons, the experiments produced large numbers of Y(4260), which lives for only 10-23 seconds before falling apart into other particles. The teams noticed that their data had a peculiar bump around 3.9 gigaelectronvolts (GeV), an energy corresponding to roughly four times the weight of a proton.
“Inspired by this discovery, we decided to further study the Y(4260) decay, which indeed did not disappoint us,” said particle physicist Zhiqing Liu, lead author of a paper from the Belle experiment that appeared in Physical Review Letters on June 17. A second paper from BESIII, of which Liu is also a member, appears in the same issue.
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