fahrbot-bot shares a report from Live Science: Scientists have finally found traces of the axion, an elusive particle that rarely interacts with normal matter. The axion was first predicted over 40 years ago but has never been seen until now. Scientists have suggested that dark matter, the invisible matter that permeates our universe, may be made of axions. But rather than finding a dark matter axion deep in outer space, researchers have discovered mathematical signatures of an axion in an exotic material here on Earth. The newly discovered axion isn’t quite a particle as we normally think of it: It acts as a wave of electrons in a supercooled material known as a semimetal. But the discovery could be the first step in addressing one of the major unsolved problems in particle physics.

The research team worked with a Weyl semimetal, a special and strange material in which electrons behave as if they have no mass, don’t interact with each other and are split into two types: right-handed and left-handed. The property of being either right- or left-handed is called chirality; chirality in Weyl semimetals is conserved, meaning there are equal numbers of right- and left-handed electrons. Cooling the semimetal to 12 degrees Fahrenheit (minus 11 degrees Celsius) allowed the electrons to interact and to condense themselves into a crystal of their own. Waves of vibrations traveling through crystals are called phonons. Since the strange laws of quantum mechanics dictate that particles can also behave as waves, there are certain phonons that have the same properties as common quantum particles, such as electrons and photons. [Study co-author Johannes Gooth, a physicist at the Max Planck Institute for Chemical Physics of Solids in GermanyGooth] and his colleagues observed phonons in the electron crystal that responded to electric and magnetic fields exactly like axions are predicted to. These quasiparticles also did not have equal numbers of right- and left-handed particles. (Physicists also predicted that axions would break conservation of chirality.) “It’s encouraging that these equations [describing the axion] are so natural and compelling that they are realized in nature in at least one circumstance,” said MIT theoretical physicist and Nobel laureate Frank Wilczek, who originally named the axion in 1977. “If we know that there are some materials that host axions, well, maybe the material we call space also houses axions.”

The research was published in the journal Nature.

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Source: Slashdot – Physicists Have Finally Seen Traces of the Long-Sought ‘Axion’ Particle