April 13, 2014
Newly Discovered Particle Could Be The First Ever Confirmed Tetraquark
redOrbit Staff & Wire Reports - Your Universe Online
The Large Hadron Collider (LHC) has already played an essential role in the discovery of the so-called God particle, and now the world’s largest particle collider may have helped scientists discover a new form of matter known as the tetraquark.
According to Maggie McKee of New Scientist, researchers conducting experiments at the LHC have confirmed the existence of a particle known as Z(4430). While physicists had previously theorized that this particle exists, it had never been observed before – and now that it has, it could be the strongest evidence yet that the tetraquark exists.
Quarks, which are subatomic particles that serve as the fundamental building blocks of matter, are known to exist in either pairs or groups of three. In pairs, they form short-lived mesons, while in groups of three, they form the protons and neutrons that comprise the nucleus of an atom, explained Mashable’s Jason Abbruzzese.
Scientists have suspected for decades that groups of four could also bind together to form a quartet, thus forming a tetraquark. However, they previously have been unable to complete the complex quantum calculations required to test and verify those beliefs.
The newly discovered particle, Z(4430), is believed to be one of these tetraquarks, and in the recent LHC experiments, up to 4,000 of the particles were discovered. Now that its existence has been confirmed, the physicists will attempt to determine whether or not it truly is a still-hypothetical tetraquark.
Physicists have at least one reason to be hopeful, McKee said. While other suspected tetraquarks could be nothing more than loosely-bound pairs of mesons, Tel Aviv University physics professor Marek Karliner explained that Z(4430) is different because of its mass. “There aren't any mesons at the right masses to make such a thing,” he explained, suggesting that it is an actual particle quartet.
There is one mystery remaining, Karliner (who was not involved in the research) told the New Scientist reporter. The decay rate of Z(4430) is at least 10 times faster than previous tetraquark suspects, which does not mesh with models of the particle group’s behavior. Additional data on how this particle decays could reveal whether or not is truly a tetraquark, and potentially lead to new insights into how matter behaves at the most basic scales.
The LHC team’s findings are currently available online at arXiv.org.