Researchers have confirmed the existence of exotic hadrons, which are a type of matter that could not be confirmed through the common quark model.
"We've confirmed the unambiguous observation of a very exotic state-something that looks like a particle composed of two quarks and two anti-quarks," Tomasz Skwarnicki, a professor and specialist in experimental high-energy physics, said in a Syracuse University news release. "The discovery certainly doesn't fit the traditional quark model. It may give us a new way of looking at strong-interaction physics."
Quarks are "hard, point-like objects found within the nucleus of an atom," the news release reported. When three quarks band together they form compound particles called baryons; a commonly-known baryon is a proton.
When these particles interact with anti-particles that have the same mass but an opposite charge, called anti-quarks, they make up mesons. These typed of compounds can be found when heavy man-made particles such as those found in nuclear reactors decay.
In 2007 a research team known as the Belle Collaboration discovered an exotic particle, dubbed Z(4430), which seems to contain two quarks and two anti-quarks.
"Some experts argued that Belle's initial analysis was naïve and prone to arrive at an unjustified conclusion," Skwarnick said. "As a result, many physicists concluded that there was no good evidence to prove this particle was real."
As second research team called BaBar conducted an analysis the called Z(4430)'s existence even more into question.
"BaBar didn't prove that Belle's measurements and data interpretations were wrong," Skwarnicki said. "They just felt that, based on their data, there was no need to postulate existence of this particle."
Belle conducted an even more thorough analysis of the data set and found "statistically significant" evidence of the particle's existence.
"We analyzed tens of thousands of meson decays, selected from trillions of collisions in the Large Hadron Collider [the world's largest, most powerful particle accelerator] at CERN. Because the data sample was so large, it forced us to use statistically powerful analysis that could, in turn, measure properties in an unambiguous manner. It's great to finally prove the existence of something that we had long thought was out there," Professor Sheldon Stone. of the European Organization for Nuclear Research (CERN), said in the news release.
"Each experiment--Belle, BaBar, and LHCb--analyzed its own data. Although it pertained to the same process, the data was collected at different times, with different colliders, and with different apparatuses for capturing outgoing particles. Our findings are unique to our experiment," Skwarnicki said.