Parity was long thought to be a fundamental law of nature. It essentially states that the universe is neither right- nor left-handed — that the laws of physics remain unchanged when expressed in inverted coordinates. In the early 1950s it was found that the so-called weak force, which is responsible for nuclear radioactivity, breaks the parity law. However, the strong force, which holds together subatomic particles, was thought to adhere to the law of parity, at least under normal circumstances.

Now this law appears to have been broken by a team of about a dozen particle physicists, including Jack Sandweiss, Yales Donner Professor of Physics. Since 2000, Sandweiss has been smashing the nuclei of gold atoms together as part of the STAR experiment at RHIC, a 2.4-mile-circumference particle accelerator, to study the law of parity under the resulting extreme conditions.

via For One Tiny Instant, Physicists May Have Broken a Law of Nature.