The Anomaly at Atomki: Have Scientists Really Found a Fifth Force of Nature?

The possible discovery of a new particle in Hungary, and its subsequent interpretation as the force behind dark matter, has kicked up some dust. However, something’s off about the Hungarian results…

Vasudevan Mukunth in The Wire:

It’s called the Atomki anomaly. ‘Atomki’ is the nuclear physics research centre at the Hungarian Academy of Sciences in Debrecen, Hungary, and the site of a certain experiment that first spotted the anomaly about two years ago. Though there are some doubts about what really has been found, the news of something being anomalous at all – a new particle? – has stoked excitement in a community desperately looking for something new. In fact, one interpretation would have us believe that, if other tests around the world are able to hold up the Atomki results, it could be a phenomenal new discovery: of a fifth fundamental force in nature, possibly related to dark matter.

In the experiment, scientists fire protons at a lithium atom. A lithium atom contains four neutrons and three protons. When it captures an extra proton, it transmutates from a lithium-7 atom into a beryllium-8 atom, 8 being the new sum of protons and neutrons: four and four. However, the stable beryllium atom needs five neutrons and three protons, so it starts to lose the extra proton’s worth of energy through radioactive decay. In this process, the beryllium-8 atom emits a photon that then decays into one electron and one positron (the electron’s antimatter counterpart).

More here.