Dirac's equation can no longer be considered mysterious, given its central position in modern physics. But 60 years later, some of the equation's features have yet to be explored experimentally.

Scientists have recently identified a particle known as the Dirac semi-fermion, exhibiting behavior that defies expectations.

Semi-Dirac fermions are somewhere between Dirac ... lead author and Penn State physicist, said in a university statement, “and it turns out we had made the first observation of these wild ...

"This was totally unexpected," said Yinming Shao, assistant professor of physics at Penn State and lead author on the paper. "We weren't even looking for a semi-Dirac fermion when we started ...